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disk service manual iii

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1. 80 640 161 280 161 280 322 560 256 256 512 512 512 512 1 025 024 Based 35 Tracks Sida Based on 18 Sectors Track 128 byte sec Based 18 Sectors Track 256 bytes sec Chapter i i is a complex i i rives to their computer systems is a ds difficult to ferret out god parent one an Bie can be caused by the drive mechanica cable electrical and or the computer onic A bad controller part mener Manite itself as ap pps da configured drive DOS software bugs f all apparent drive problems relatin oe angle tive Only caused by malfunctioning drive a ba i i i ling or connection If more than one DOE type of problem when teteg vith oe good diskettes in 95 of the cases the probler is NO by the drive or by the diskettes but b something in ae to all rives in the system drive cable multi drive NEL s controller uP RAM Except in the case of a major mechanical most problems system caused by the malfunction of only a single part d drives are lemons D some computer systems an s pi MUN designed and constructed that you may NEVER mpletely ferret out all problems If problems compoun or solution
2. CHAPTER XII CHAPTER XIII APPENDIX A R DRIVE ANALYSIS SOFTWARE CRITIQUE ers o GENERAL OPERATION ADVICE amp TIPS ERROR MESSAGES DIAGNOSTICS TROUBLESHOOTING MAINTENANCE SPEED ADJUSTMENT W HEAD ALIGNMENT ELECTRONICS amp REPAIRS MISCELLANEOUS REPAIRS DRIVE TEST STATION REPAIR SHOP TECHNIQUES DRIVE MODIFICATIONS GLOSSARY ISTA N COPYRIGHT 1986 JOHN J WILLIAMS and FAMILY ABSOLUTELY ALL RIGHTS RESERVED By John J Williams MSEE CONSUMERTRONICS CO P O Drawer 537 Alamogordo NM 88310 EALERS AND INSTITUTIONAL BUYERS COD 20 offers substantial discounts for quantity buys Also ior quanti of 50 or more of this or of other CONSUMERTRON ICS CO publication we can publish a special printing or edition to meet YOUR SPECIAL NEEDS This is a fantastic opportunity for you to deal in our publications and or to promote your business or institution Changes may include 1 Additions deletions and changes sizes typestyles colors materials formats and arrangements binding and or mode of re duction Pay Addisons deletions and changes in the copy Proprietary items such as logos ads photos text and illustrations must be e e9090909999099909999999999999999999999999999999999999999 29244 vided by you camera ready For non propri
3. 89 AEG WRITE DATA WRITE T00 SENSOR WRITE READ DATA SIDE SELECT RESERVED READY 9999 9999999 9989 9 9 2 8 STANDARD BUS 5 STANDARD BUS MELLE u yap ting Chapter REPAIR SHOP TECHNIQUES When we used to rely upon professional drive shops we discovered that they often changed jumpers drive select etc and TRNs so that we would have to reconfigure the drive to again work in our sys tem And our 42 TK drives were adjusted to 40 TK only In remov ing packing shipping unpacking reconfiguring re installing and re testing the drives we ended up doing much more work than when we serviced the drives ourselves And there was always the risk of further damage and deterioration just from the additional handling and shipping PROFESSIONAL DRIVE SHOPS Sophisticated shops use a specially programmed controller usually pP based whose function is to exercise disk drives This set up is called an Exerciser It takes about 30 minutes for a professional drive shop to properly align drive that is only radially misaligned They use a special 572 DYSAN other 55 DS Cat s Eye Alenment Diskette with a high frequency signal on T16 and 52 000 differential type oscilloscope Because of the amount of set up required it would take you 2 3 times longer t
4. POWER GROUND SYSTEM DISK SERVICE p COMPUTER MANUAL vi AC wama qu DISK VOLTAGE REGULATOR PRINTER LECTRONICS tora amp REPAIRS 120 VAC LINE MISCEL 2 Consumertronics Co 2011 CRESCENT DR P DRAWER 537 ALAMOGORDO 88310 KEY DRIVE DRIVE SELECT J SLOT JUMPER BLOCK PIN 3502111 D amp 1 N P1CONNECTOR SCOTCHFLEX PIN 2463 0001 OR AMP PIN 583717 5 COV P2 CONNECTOR FRAME CONNECTOR FRAME GROUND AMP PIN 1 480424 0 AMP P N 60972 1 AMP PIN 61664 1 DRIVE CONNECTOR HOOKUP SHUGART ASSOC HOT BLACK FUSE O 22 lt 1 V 100K cho ot NORMALLY OPEN TO 120 VOLTACE 0l uf 1 REGULATOR j PUSHBUTTON NORMALLY OPEN SWITCHES POWER CONTROLLER 120 OUTLET 8 LINE FILTER CORCOM 52 OFF NORMALLY CLOSED ALL GE VI30LAIOA VARISTORS 120 VAC 5 RELAY NEUTRAL WHITE GROUND GREEN SHIELDED POWER CABLE TIE GROUND AT LINE FILTER ONLY FUSE RATED EXCEED TOTAL SYSTEM RATING AND LESS THAN 50 REGULATOR RATING RELAY CONTACT RATING AT LEAST EQUAL TO 200 FUSE RATING POWER CONTROLLER AC DISTRIBUTION 3 WIRE TWISTED PAIR CABLE 12 GUAGE FOR MICROCOMPUTER SYSTEMS DC DISTRIBUTION SEPARATE TWISTED PAIR CABLE FOR EACH DEVICE 20 OR 18 GUAGE GROUNDS ONLY ONE CONNECTION PER FRAME FOR ALL DC AND AC
5. CLIFFORO honk Co 2011 CRESCENT DR DRAWER 537 ALAMOGORDO NM 88310 Publishers Of Invaluable Edid Information m eed PRN A Bis D PEE E uj BiBi de N ix No r E AO COE Pees m a lt A j ERU t Aes ya 7 FHN ner TN t IM 4 2 cor 4 DE T P MU E a NV ae ae CUN DRIVE SELECT DIRECTION 57 EAD LOAD TRACK ZERO INDEX READY SEEK BEAD DATA WAITE DATA mare s sine SELECT WATE PROTECT 0 RPM 3 msec access time Stores up to 3 33M Bytes Down ird compatibility with 48 drives is included One of the new otic breeds of super dense high performance drives The 192 density is achieved by using two stepper motors one for arse Steps 48 TPI equivalent and one for fine Steps four with each 48 TPI track Requires special high quality expensive 5 skettes Uses an absolutely vertical clamping mechanism brush ss DC drive motor and on board P Half height and low power 320 can be easily used to upgrade high performance uC systems id is a recommened back up for hard drives c
6. 204 DISK SERVICE MANUAL ITI 1 ADVANTAGES 1 The J amp DDA software lets i i 1 you quickly rotational head alignment hysteresis clamping timing and read sensitivity without using oscilloscope You can set drive speed radial head alignment and sector index photode tect or position A quick test is provided so that you can quickly check out most of these factors in one fell swoop Also you can the software with a differential oscilloscope to do a more traditional alignment And the J amp M graphics are outstanding The clampin eccentricity and alignment tests graphically point out that be merely reclamping your diskette significant changes in ec tricity alignment occur eot 2 The price is reasonable 579 589 and the sof i T e t separate DYSAN DDD alignment pattern diskette opa cudesa into ona er producers may combine the DDA and DDD diskettes 3 The J amp M software is available for the IB TRS 80 Model TRS 80 Color Computer and TDP 100 KAYPRO SANYO 8 Even if you don t do your own work you DDA software determine when to Scrap or sell ou dd have them repaired It can also be used to evaluate new Or ed drives prior to purchase or during the guarantee period to ferre fou lemons to estimate remaining useful life and to evaluate repairs The hysteresis and Read Sensitivity tests can also to indi
7. o RECORD TYPE RNF RNF ANF 0 CRC ERROR CRC ERROR CRC ERROR 1057 LOST DATA ILOST DATA LOST DATA ORG BUSY BUSY BUSY DISK SERVICE MANUAL III 2 STATUS FOR TYPE COMMANDS MEANING This bit when set indicates the drive is not ready When resat it indicates that the drive is ready This bit is an inverted copy of the Ready input and logically ored with MR When set indicates Write Protect is activated This bit an inverted copy ot WRPT input When it indicates head is loaded and engaged This is a fogical HLD and HLT signals When set the desired track was not ventied This bit is reset to 0 when updated CRC encountered in ID field When set indicates Read Write head is positioned to Track 0 This bit is an inverted copy of the TROO input when set indicates index mark detected from drive This bit is an inverted of the iP input 57 NOT READY 56 PROTECTEO 55 HEAD LOACED S4 SEEK ERHOR S3 CRC ERROR When set command is in progress When reset no command is in progress STATUS FOR TYPE COMMANDS NAME MEANING S7 NOT REAOY This bit when set indicates the drive not ready When reset it indicates hat the dnve is ready This bit is an inverted copy of the Ready input and ored with
8. Control Program for pPs d Hz Cycles Per Second CPS syne Synchronous Central Processing Unit IC Integrated Circuit Chip NUR TPI Tracks Per Inch Redundancy Check word sum ID Identification or Identifier Terminal Resistor Network CW CCW Clockwise Counterclockwise IDAM Identification Address Mark l Term Resis Net DAM Data Address Mark VO Input and or Output Microcomputer Microprocessor DDA Disk Drive Analysis Software Iss Jumper Selected UNIX XENIX pC Operating Systems DDD Disk Drive Data Software K Thousands 1 0005 ups Uninterruptable Power Supply DIR N Directory List of Drive lab Laboratory Microseconds 0 000001 Second DOS Disk Operating System LED Light Emitting Diode VDC Voltage Direct Current vac Voltage Alternating Current DSn DS Drive Select dn micron Miltionth Inch 0 000001 Irich RO Rend Jobn J Williams TABLE OF CONTENTS CHAPTER CHAPTER II CHAPTER III CHAPTER CHAPTER V CHAPTER CHAPTER VII CHAPTER VIII CHAPTER IX CHAPTER X CHAPTER XI
9. ly by a capacitor by a soider hair ball splash by a stray piece metal or other conductor or by two leads accidentally press together recent handling OTHER VOLTAGE CHECK Once you ve located the probable section where the problem and you ve used the other techniques to no avail then start chec ing individual pin voltages Most systems are TTL Exce t for tr 12 VDC that goes to the stepper and spindle motors and t eir ele tronics peripheral drivers ex 12 VDC 12 VDC to RS 232C some memory ICs 12 VDC 5 VDC virtually all circuit voltag are TTL 5 VDC By measuring TTL IC pins that are connected to other electror parts one can easily tell whether or not a TTL IC is functioning cc rectly No voltage should be between 2 and 3 volts in magnitu 0 outputs are usually 1 5 volts and less while 1 outputs a usually 3 5 voits and more 2 3 volts is a floating output strong indication that that part and or one of the others connec ed to that pin is bad Check the other pins and leads connected it if any of the voltages differ then the proplem is either a disco nection between the part and the board bad solder or contact or broken board trace Use a logic probe to verify that the voltage is not a pulse volta that s just averaging out to 2 3 volts We RE recommend t one we designed see our ULTIMATE LOGIC PRO plans All grounds should be at zero volts and all power pins pins and lea should b
10. om ges ft 5 U ean eee d Y gs n MOTOR DRIVE SCRE y x Ass Mey IN INOR UNDERNEATH UNDERNEATH HEAD CARRIAGE ASSEMBLY TOO SENSOR ub pon rtp ny hc tm rt LL SA CONSUMERTRONICS ATTN John J Williams MSEE 2011 Crescent Dr P O 537 Alamogordo NM 88310 MPI B51 MPI B51 5 flippy 40 Tk drive Split band actuated Primary positive features are its rare configuration and its diskette eject mechanism Spring loaded door may be objectionable to some users Diskette eject mechanism failures are common but drive operation is not affected Some people prefer a flippy drive over DS one because if you have power fluctuations or drive electrical malfunction both sides can be glitched in a DS drive Also DS drives are more trouble prone because of th second opposing R W Head While flippy drives permit you to use both sides of the diskette without the tedium of modifying disk ettes you avoid DS drive problems and risks OWER LJ thee e gt 292452 Caas 2 leto CONNECTOR 5 wee o 14 wet sets teh mie s UPS ER TT M ia Wa a Ve gis es 8 DRIVE UNKNOWN SIEMENS FDD 100 5 SI
11. 4 1 SHOULDER x WASHER B CONE SPRING N WASHER 4 SHAFT fD ecAnING DRIVE MOTOR AND SPINDLE DISASSEMBLIES TANDON wt SPINDLE HUB a MOTO t y Sc RE SLOT REY di cr SPRING CHASSIS MOUNTING SCREWS 2 gt END STOP TANDON BRACKET a 3 picket TTC B e aui IIS D TATUM TERME s x lt 3 gt MITSUBISHI M ODEL MF353 3 5 D ISK DRIVE DS DD 80 Cylinders TKs side 135 256 Bytes Sector 16 Sectors TK 250K Bits Sec Rate 300 RPM Spindle Brushless DC Motor Direct Drive 3 msec Step TK 15 msec Settling 100 msec Latency 1 000K Bytes unformatted 655 4K Bytes formatted 200 msec Rotation 250 msec Motor Start CONTROLLER SIGNALS amp DRIVE FUNCTIONS COMPUTER FLOPPY DISKA mer TU FLOPPY DISK DRIVE rl HEAD HEAD LOAD DRIVE SELECT 3 LOAD SOLENOID ORIVE SELECT 4 SPINDLE DC DRIVE TRACK 00 SENSOR RACK od TRACK 00 Duos Er 2 DIRECTION SELECT HEAD pred STEPPER ONTROL MOTOR SECTOR INDEX SECTOR SECTOR INDEX INDEX OC SIDE SELECT DS WRITE PROTECT m WRITE L PROTEC DETECTOR WRITE GATE WRITE RASE A
12. READ YES DISKETTE READ NO DISKETTE 1 NOTE 3 ERROR ERROR RUN READ TEST NO YES RUN TRACK SEEK HARDWARE TEST ERROR NOTE 35 HAROWARE SWAP ERROR YES ERROR DISKETTE ORIGINAL mi RON DISKETTE NOTE 4 WRITE VERIFY BAD TEST DERIVED FROM RADIO 7 FINISHED SHACK DISK DRIVE MANUAL HAROWARE ERROR NOTE 26 DISK SERVIC MANUAL HOLDER CLAMP ARM STEPPER MOTOR SPINDLE MOTOR JMOTOR MOUNTING SCREWS STEPPER c w 2 229 PAPC MOUNTING REW HEAD CARRIAGE ASSEMBLY TINSULATED SEAT KUNDER PC BOARD DIAGNOSTICS amp TROUBLESHOOTING TEAC FD 55 DISK DRIVE Chapter V MAINTENANCE The three most important wear factors that determine the mechani cal life of a drive Head cleanliness Lubrication of the guide rails and mechanical linkage to the stepper motor motor and pully lubrication Less of a factor is stepper motor lubrication because stepper motors are used less use better bearings and retain their factory lubrication longer properly cared for drive can last 20 years of regular use A poorly cared for drive can die within a year Many drive service manuals and articles tell you to never lubricate your drive no matter how tempting and that drive motors are Jubricated for the life of the drive This is bull Like any preci
13. or counter hook up to the sector index signal Puises should be at 5 Hz or 200 msec period and constant to within about 1 Head radial alignment can be performed with the Drive Test Sta tion an oscilloscope and a standard CE diskette See alignment chapter Hook up the dual trace oscilloscope directly to the output of the Read Write head Select A B differential setting Loosen the head assembly screws Gently adjust the alignment cam screw or stepper motor depending upon drive model until the signal is strongest Gently retighten the head assembly screws while constantly rechecking signal level Alignment can also be done with the simple circuit shown without an oscilloscope and with without a CE diskette The Drive Test Station can also be used to adjust the TOO sensor and TOO end stop simply by using it to Step the drive back and forth between TOO and 01 see alignment chapter We are interested in all experiences insights enhancements and m ifications you have regarding this or any other disk drive test c it 5 80 MODEL Our primary disk drive evaluator TRS 80 Model which we use in conjunction with the Drive Test Station Any other microcomputer could also be made to work Although the TRS 80 Model itself is obsolete 100 000 are still known to be in regular use it can thoroughly test and evaluate more drive types and models than any other non dedicated microcom
14. RECOMMENDED TOOLS The following tools and supplies are necessary for drive mainten ance and repairs Be sure that before you start you have your work area set up with all tools and supplies at hand so that you don t have to be disturbed looking for them during a critical opera tion You may need additional tools to physically access your drives 76 located in a computer or expansion interface Use proper ground 2 the right tools and supplies and never rush D 1 SCREWDRIVERS One medium blade at least 4 long One fine blade at least 6 long One medium phillips at least 4 long 2 OTHER TOOLS Allen wrench set Long nose pliars Diagonal cutters Small wooden mallet Smal hand mirror Pen light with extension Soldering iron 3 SUPPLIES Cotton swabs 6 stem JASCO AUDIO ACCESSORY or equivalent Blank and formatted diskettes DOS diskette Bath towel or cushion Pencil and paper Wire Elec trical tape Lubricants and chemicals see below 4 OPTIONALS Disk diagnostic software CE DDA DDD 50 100 MHz oscilloscope with A B differential capability 2 8 channesl 1 10 probes Circuits described herein LUBRICANTS Light machine oil sewing machine oil 3 IN 1 or WD 40 are recom mended as drive lubricants Do not use a silicone or graphite based lubricant The oil can be dispensed with a spray nozzle hypodermic injection or by cotton swab Even though most repair experts do not recommend WD 40 we ve use
15. assembly m u in most drives Precision bearings are pressed PA Weed depuis sides of the frame where the spindle passes through There should a or sleeve between the bearings to keep them apart Depending upon the am i i fot have ount of their wear the bearings may may Once the pully screw is removed the pully can be safely twisted off In some drives that don t have hex head screws between the hub and the frame the remainder of the spindle assembly can be removed by pulling and twisting on the hub in others the spindle assembly is installed by cement bonding and can t be replaced Else remove these two hex head screws and rotate the hub CCW until you can pull it out The new spindle assembly is installed in the reverse order of its removal HEAD CARRIAGE ASSEMBLY Replacement of the head carriage assembly or module assembly carriage assembly stepper motor is so expensive and difficult that it almost always pays to replace the drive itself please donate the drive to us for spare parts It always requires re align ment of the head s and usually re adjustment of the TOO sensor Removal of the logic and servo motor boards and the cone lever assembly are also required Virtually every drive model uses a different procedure In most drives the entire module assembly head carriage assembly stepper motor assembly is replaced as one unit in others you can separately replace the h
16. eimi mA en nma uma a ER 5 Ls Mela eios Toth 32 asam San BET RARI a ca e 562 A de k yaaa M 1 a a Ce S ET E PENE E A E E ET E CONNECTOR 2 DRIVE FRONT PANELI SHUGART SA 465 5 DS 80 Tk half height drive Split band actuated The i band actuator is held under spring tension to compensate for contraction This tension also has a damping effect on the band resulting in quieter operation Very high quality drive Never had a problem with them Has numerous positive features The spindle hub turns when you are inserting a diskette which provides for much improved clamping The dynamic clamping mechanism also brings the cone vertically down onto the diskette and not at an angie as in most drives The spindle motor directly drives the spindle no belt which permits a circular not elliptical spindle rotation The spindle motor is brushless direct drive and is 60 smaller than in most other drives The reduced internal friction of its new stepper motor also reduces average access time from the 150 275 msec of most floppies to 9 amp msec Far fewer electronic components go into its design The 5 465 dissipates about 50 of the power that older drives dissipate Two SA 465s can be operated from the same power supply and occupy the same cabinet space as one full size 35 40 Tk drive By doing so you will h
17. P4 AMP P N 1 480303 0 AMP PIN 1 480304 0 SHUGART PIN 50606 CONNECTOR FLAT CABLE 3M PIN 3415 0001 TWISTED PAIR 1 583717 1 VIKING PIN 3VH25 1JN 5 wa ss s s s s x s m w w u tl INTERFACE CONNECTORS PHYSICAL LOCATION DIAGRAM Memes um um uei ee m m 9 I 5 V RETURN 2 24 V RETURN AC INPUT g FRAME GROUND AC INPUT FRAME GND 2 TWISTED PAIR POWER CONNECTORS 1 2 3 DISK SERVICE MANUAL III DRIVE ANALYSIS SOFTWARE XII 2 so to us the J M software didn t provide signific nt help t adjust the photodetector 5 The J amp M DDA software may not appl drives that your system can use tion includes a TRS 80 Model to all the types of For exampfe our drive test sta The J amp M DDA software we pur chased is good for 5 SS SD drives only the only available J amp M Software for the Model I It is useless for testing our 80 Track DS 8 and other drives other systems J M software for other drive types are also available but are individually priced APPLE DRIVE LEVER ASSEMBLY Consumerironics Co 2011 CRESCENT P O DRAWER 537 ALAMOGORDO 88310 m 170 253 FRAME GND 170 253 V RTN 85 127 FRAME GND 85 127 RTN
18. The filespec was too long or con DISK SERVICE MANUAL ERROR MESSAGES 10 FILE NOT OPEN The Directory Fil OPEN priae ta s READ WRILE y File Control Block was not OTHER COMMON ERRORS 1 PARITY or CRC ERROR DURING READ WRITE A CRC or checksum error resulted from Reading Writing the data field of a sector the user data examined did not compute to the correct CRC or PARITY CRC ERROR DURING HEADER READ A CRC checksum error resulted when the DOS i Read Write ID but couldn t find the correct sector Usual ly due to a glitched diskette Can be due to Sector Index out of adjustment A neadon error is rare and indicates or controller because the header sh i A except during a Ould never be Written DURING READ WRITE The head won SEEK properly during a READ WRITE The track found as Read the sector header does not correspond to the track that should be at that physical position of the head due to head misalign ment or diskette eccentricity 4 SECTOR TRACK NOT FOUND DURING READ WRITE The ertor E number was not found the current sector AD gurin Se n e error is displayed ailed attempts Means the thin and 3 TRACK above 5 DATA RECORD NOT FOUND DURING READ WRITE Same as 4 above i 6 LOST DATA DURING READ WRITE The software was too slow for t
19. 85 127 FRAME GND 85 127 RTN 170 253 FRAME GND 170 253 V RTN 0 07 0 05 A TYP 0 10 A MAX 0 07 A TYP The 24 V dc power requires a separate ground return line The 24 V return Other ground return lines and frame ground must be connected logather at he main power supply Not required LSI PCB s VOLTAGE SPECIFICATIONS 200 Ono 50574 21 J4 CONNECTOR 800 801 POWER SUPPLY 50574 20 FICATIONS SPECIFICATIONS SHUGART J5 CONNECTOR Chapter XIII DRIVE MODIFICATIONS SHUNTS amp JUMPERS Early floppies contained only a few selectable features and options These included DS Drive Select MX HS HM and a few others Modern drives offer dozens of features and options Most of these can be selected by using the provided socket connected jumpers and or post connected shunts called provided JSs here Manu facturers service maintenance OEM manuals provide for features and options that require either cutting logic board traces and or soldering jumpers some in combination with provided JS changes Each drive model has its own options set up In every known case all mods are done on the logic board In some drives they are rouped into one area but in others they are scattered all over the ogic board Should you be uncertain how to make JS changes refer to your particular drive manual Some of the possible
20. P O Drawer 537 Alamogordo NM 88310 rye MR S n rre REFERS MOTOR TANDON TM 100 DRIVE TANDON TM 100 1 5 SS 40 Tk split band actuated 100 2 is the DS ver sion Except for the ALPS drives used in APPLE COMMODORE ATARI and other non standard bus drives the TM 100 is the most popular drive in the world Earlier versions were limited to 35 Tk Many variations in Logic Board circuitry Requires frequent drive motor speed adjustments Most frequent cause of sud 3 den misalignment is loose collar on the stepper motor shaft Also the tlip out EN Ru 19 doors as with other drives with flip out doors tend to easily break We consid ge HEAD CARRIAGE er the TM 100 to not be of highest quality and apparently overpriced 54 ASSEMBLY 1 Re OT 17 NF LOGIC BOARD Aa de a CONSUMERTRONICS z C ATTN John J Williams MSEE 2011 Crescent Dr P O 537 Alamogordo NM 88310 SHUGART SA 460 SHUGART SA 460 5 DS 80 Tk drive The 5 810 is the SS ver sion In spite of being lead screw activated we operate ours at 6 msec stepping in our most critical uses SA 60 is no longer made by SHUGART yet it is a high quality and reliable drive Highly recommended EINER e 2 4 a obo CE mm Se
21. be extremely difficult and time consu A PARTS SUBSTITUTION i fessional shops can be extremely costly Satona le IBM EU al at this writing 120 hr two hour mini tum re ardiess of the problem for labor alonel Other computer mak rs and shops charge similar stiff fees All of the major er nakers we were able to check 11 of them made 25 35 their total 1985 incomes from their repair Ead Belt snae ds i k you might as w alone For five hours of shop work s e new It can pay you 5 brisk sales of our DISK SERVICE ME DAT DISK DRIVE TUTORIAL PRINTER amp PLOTTER L COPIER MANUAL etc attest to the great interest people have in repairing their own equipment and in doing it themselves ur troubled system to a repair shop and hard s their solution yon mostly consist of the parts substitution method Repair on hand spare drives Logic and Servo Motor boards o They usually first swap out aie and subsystem level they re assemble your system a arge yot s board power supply etc when the pr Ol p IC requiring minute of repair time An Pc ns replacement about 5800 They may then 1 tempt to repair your board or subsystem to sell to the next cus tomer at full or return it to the factory for a replacement i id that pro repair shops charge you 400 for
22. sion mechanical instrument drives must be periodically lubricated or they will wear out and break down What is really meant by life time lubrication is the life of the lubrication not the possi ble life of the drive Of course you can over or incorrectly lubri Cate drive gt that too must be avoided PROCEDURES First turn OFF power to the drive and disconnect To perform periodic maintenance 1 Clean and lightly lubricate drive mechanical components frequent 3 an the drive Read Write head s and felt pressure pad i quent 3 Clean and or align the index hole optical coupler s quired rare 4 Verify the write protect notch detector s and adjust IF requiced rare Verify drive speed and adjust IF required frequent in some drives impossible in others 6 Verify alignment of Read Write head s and align IF re quired occasional to care 7 Verify the TOO sensor and TOO end stop and adjust re quired 8 Inspect for electronic defects and correct IF required rare 9 Clean drive connectors frequent if not gold plated rare if gold plated There is a subtle difference between the meaning of align and adjust Align means to set precisely to an absolute position even though a sloppier setting would still function Adjust means to set to a position so that a function ex TOO sensor switching reliably occurs a precise setting is not required
23. FARAGAT SRILDCO ISOLATION TRANSFORMER FOR yf gt CREER SAFETY D FRARSIENT SUPRESSORS Li towsqut INTERNAL BOND RACKS METALIZED PANELS NAEINFORCED 11004 7 ua 465 FLOOR ISOLATED gt REIAL PARTS EXCEPT OME COMMECTION NOTES 10 SAFETY WIRE ANO METAL FLOOR GEOUNO LOOPS AMBICT MISSION EITHER BOND CABINETS CONSOLES 19 METALIZED FLOOR AND SISTRIBVIE POWER WITHOUT METAL SAFETY WIRE 21 00 WOT 96 0 CAOINETS ARD CONSGLS 10 METALIZE FLOOR 015769077 POWER UL CONDUIT WITH SAFETY WIRE DISK SERVICE MANUAL III ELECTRONICS amp REPAIRS _ a drive function fails ex TOO sensor function and the failure can t be traced to an external unit that may be a part of that func tion then switch or substitute the drive to verify that the defect is in that drive and not in the system or interface VIII 4 The best method to pinpoint the problem to the logic board is to switch the logic board with one in another known good same model drive If after the PC board switch the problem also switches drives then a circuit in the logic board is very likely bad If the problem doesn t switch with the board then the problem is in some other part of the drive If both drives are now bad the proble
24. amp M speed tests t work software indicator does not seem to follow positions of the hotodetector In the drives we adjusted the indicator seems to Jump all over the place It sometimes indicated photodetector movement when there apparently wasn t any and indicated no movement when it was being moved Also tightening and loosen ing of the photodetector screw profoundly affected the reading Perhaps all of these anomalies can be physically explained Even small drift Our optically coupled digital counter independently checked the fluorescent lamp as 60 Hz 0 1 Also if your system has a speed modification clock speed up kit unless you can switch back to the designed in speed the J amp M speed tests t work s software indicator does not seem to follow positions of the photodetector the drives we adjusted the indicator seems to jump all over the place It sometimes indicated photodetector movement when there apparently wasn t any and indicated no movement when it was being moved Also tightening and loosen ing of the photodetector screw profoundly affected the reading Perhaps all of these anomalies be physically explained Even DRIVE PCB 15 1 280999 0 SHUGART PIN 15641 Jt AC DRIVE MOTOR CAPACITOR EG i 27 NC 5 PIN 1 480270 0 SHUGART PIN 50605 REAR OF DRIVE 14 PIN 1 480305 0 SHUGART PIN 10150
25. head misali 1 i ignment or con taminated Read Write Head and occasionally by ware failures A Soft READ Error is defined as a READ error which can be re covered in less than 11 attempts to Read a record If a record has not been recovered after 4 re attempts restore the drive to T00 re Seek to the specified track and Read with a maximum of 5 ad ditional attempts I the record is Read properly the error is de fined as a Soft READ Error If the record is still not Readable it is defined as a Hard READ Error Soft and Hard READ Errors are caused by the same factors that cause Soft and Hard WRITE Errors WRITE ERRORS A WRITE Error is defined as a record which canno Read after ten READ attempts during Read after Soft WRITE Error is a WRITE Error which can be recovered in less than 5 Write attempts Soft WRITE Errors are caused by defective media diskette low signal to noise ratio incorrect or erratic drive speed contamination worn felt pressure pad and or minor head misalignment Restoring he EDC computed from the t be successfully Write routine H the record is not Read properly during a Read after Write rou tine after 4 WRITE attempts the error 15 a Hard WRITE Error In the case of a Hard WRITE Error the sector or track should be locked out as defective More than two Hard WRITE Errors per sur face calls for diskette replacement Hard WRITE Errors are caused by the same factors that
26. systems this voltage is 5 volts To wire the toggle switch to Jl 32 for side select trace the PC land from 21 32 to a clear point where you can solder your toggle switch contact Clean off any land coating and solder one Contact of the toggle switch to this clear point Use 26 guage stranded plastic insulated wire Solder the other end of the switch contact to any signal ground point When you switch the toggle switch Side 1 will be forcibly select ed regardless of what the computer thinks it selected m f 0 TOR ge 5 DYNAMIC SPEED GUAGE COMMODORE 1541 DISK DRIVE BOTTOM OF THE DRIVE ASSEMBLY FRONT PANEL Consumertronics Co 2011 CRESCENT DR DRAWER 537 ALAMOGORDO NM 88310 3 JUMPER WIRE ADDED TO ALL DRIVES 7 1 RESISTOR TERMINATION SOCKET REMOVE EX FOR ORIVE NUMBER ZERO 2 OW SHUNT PACKAGE PN DIP SITS UP PER PART 14 PIN DIP SOCKET MUST BE PUNCH SHOWN W ALL DRIVES RESISTOR TERMINATION TRN DIPSHUNT AND JUMPER TANDON ISTOR TERM OF SHUNT BLOCK SOCKET AND RES SOCKET IN CDC SHUGART AND TANDON DRIVES KEYED CONNECTOR 11 DRIVE SELECT SIDE SELECT UNKEYED CONNECTOR 21 SWITCH B SWITCH A Selects DS 2 drive b configuration SWITCH B Selects SWITCH a command or selects Side 0 b or Side HOW TO MODI
27. the drive must be kept turning long enough to adjust the spee po See miscellaneous repairs or alignment chapter FAM poner keeping the drive turning using the DOS or drive so iioi one method is to use a machine language loop routine t at con inua y commands Motor On Still another 15 to use the Drive Test Station see that chapter DISK SERVICE MANUAL III SPEED ADJUSTMENT of the light on the pattern The strobed pattern may be only faint ly discernable and appears yellowish Otherwise the strobed pat tern will appear to be drifting CW or CCW Slowly adjust the speed pot in the applicable direction to try to stop the drifting Small residual fluctuations in drive speed are expected with drives resulting in small drift and jitter in the strobed pattern ing method used keep the drive turning is simp An easier Motor On signal 31 16 standard bus In ANDON 5 drives this be done jumpering TP10 ground to TP13 Motor On Don t be worried harming s know all drives use pull up resi hese for a term resistor block cup ed by shorting out e FU accidentally connected up drives reversing 31 Neither the drive nor computer were Turn OFF system power and replace the drive enclosure Turn ON ower and try Reading and Writing to a diskette formatted in a kriown good drive If the problem is still not corrected
28. 15 made to Used with 255 Read attempts per LOAD repeatedly Read DIR N d one can keep the drive continuously trying to Read a track for minutes To restart just hit RESET IF IT FAILS 1f after 20 attempts an alighment can t be made or an aligned drive won t stay aligned probable Read Sensitivity problem sus ct Loose stepper motor module assembly screws loose contact etween the stepper motor and the head carriage assembly azi muth misalignment bad stepper motor loose collar loose or malad justed sensor or end stop dirty stiff or missing felt pressure pad dirty or poorly lubricated guide rails or worn or defective spindle or clamp Inspect these areas make applicable corrections and attempt to re align again you still can t find an alignment area return the cam screw or motor body to its start position retighten the screws install the enclosure and seek professional help in mind that an alignment is only as good as the mechanical condition of the equipment The best factory alignment in the world won t correct excessive wear or mechanical or electronic malfunction Drives that won t stay aligned or that have continuous problems accessing end tracks are probably excessively worn and should be scrapped Kee DISK SERVICE MANURL III R W HEAD ALIGNMENT When finished with the alignment turn n t the compute and install the drive enclosure With the drive fully reconnected turn the system ba
29. 22319032441 00 A1IATIO v S3NI 153138 010313070317 123135 00 7 qyO1 4315 Benen MANUAL ITI COMMODORE SYSTEM DRIVE BLOCK DIAGRAM MISCELLANEOUS REPAIRS DR IM LIB 13538 349315 1031098 gt YO 0193130037 2 1 i ALUM 1991094 ILIUM 123135 51501 32012 835 van Ov3u viv 438 1 0 H012313G 1931094 031 1931088 T Consumertronics Co MOTOR DRIVE LOGIC 2011 CRESCENT DR DRAWER 537 ALAMOGORDO NM 88310 m Ey APPLE SYSTEM DRIVE BLOCK DIAGRAM DISK SERVICE SA 800 801 FUNCTIONAL DIAGRAM SHUGART AMP OUT DECODER INTERFACE 2 W3211 0 0 ONY warden 339vN3 ONY 5 3 vM3 311u ASRS ALIYM 1081802 MOTOR GENERATOR READ AMP 1231084 WRITE ININA WRITE AMP READ PREAMP CONTROL STEPPER PREAMP QUT COMPUTER INTERFACE 1 WRITE DATA READ PREAMP 5 2 E lt 2 5 9 z
30. COMMODORE drives The number one APPLE and COMMODORE drive failure mode is head failure or misalignment due to frequent bumping 7 A major culprit involved in most drive taures includin misalignments is overheating Drives must be properly ventilated during all operational times Excessive heat causes minute dimen sional changes that increase friction dries up lubricants and fries the Read Write head DIAGNOSIS The most common drive errors for marginal misalignments and hysteresis are CRC or Parity errors Misalignments and hysteresis severe enough so that the track can t be found result in SEEK errors Marginally aligned drives usually take an excessive amount of time to READ WRITE due to frequent re SEEK attempts Also it may work fine when cold but loses dependability when warm or vice versa due to minute but significant thermally induced dimen sional changes In single drive systems minor misalignment may not be a problem Only when it must do a READ WRITE operation using a diskette Formatted by an aligned drive will problems develop The symptoms of radial and azimuthal misalignments are simil These include frequent Read and Write errors and incompatibility between drives The distinction is that azimuthal misalignment seldomly cause boot problems whereas boot problems is another major symptom of radial misalignment Sensor and end stop maladjustment problems manifest themselves as booting and incompatability probl
31. GROUNDS TO POWER CONTROLLER WHITE POINT E s CHASSIS CAPACITORS IN uf oe RECOMMENDED DISTRIBUTION PRINTER PLOTTER COMPUTER DISK DRIVES POWER SUPPLY COMPUTER Consumertronics Co 2011 CRESCENT DR P O DRAWER 537 ALAMOGORDO NM 88310 2 VIII 3 DISK SERVICE MANUAL ELECTRONICS amp REPAIRS Erase delay Write gate output U213 pin6 gate output my 57 Side select gate uet TIE output Head common write data input 0302 pinlli p p n nn n Data lacch output U302 pin9 Data latch output EE wie PE MES 0302 ping write current T Magnetization EE 7 Magnetized previously WRITE CIRCUIT WAVEFORMS TEAC CORP disk Shoulder Pre amp output approx TP7 ev pre amp output approx 8 Saddle Differentiation 6V approx amp output TPS 55 point Differentiation OV approx amp output peak detector T0354 pind TEAC CORP READ AMP amp PEAK DETECTOR WAVEFORMS COMPUTER ROOM SHOWING SINGLE PONT GROUNDED ISOLATED CONDUCTING FLOOR SCHEME SUPPLY MAN PORER DSTEMTION t OISCORNECT
32. MR The Type and Commands will not execute unless the drive is ready 55 WRITE PROTECT On Read Record Not Used Oa Read Track Not Used On any Write It indicates a Wate Protect This bit is reset when updated S5 RECORD On Read Record tt indicates the tecord type code from data field address mark WRITE FAULT 1 Deleted Data 0 Data Mark On any Write indicates a Write Fault This bit is reset when updated 54 RECORD NOT when set it indicates that the desired track sector or side were not lound This bit is FOUND ANF reset when updated 53 ERROR 54 is set error is found one or more 10 fields otherwise it indicates error in dala field This bit is reset when updated 52 LOST DATA When set it indicates the computer did not respond 10 in one byte time This bit is reset to zero when updated 5 1 DATA REQUEST This bit is copy of the output When set it indicates the DR is full on a Read or the OH is empty on Wnte operation This bit is rese 10 zero when up daled So Busy When set command is under When reset command is under execuhon Consumertronics Co 2011 CRESCENT DR P O DRAWER 537 ALAMOGORDO NM 88310 aan s M NL e hapter XII DRIVE ANALYSIS SOFTWARE CRITIQUE The following fians produce DDA software 1 amp SYSTEM
33. OFF p any system repair work without first tirne o the system Entire computer syst stroyed simply because someone moved a When removing or replacin ne irmly and uniformly Do not force a Connector as farce rat d age or short contacts Before turning power ON be sure th t all connectors solidly and squ rely connected sure that ALL non gold plated printed circuit b C ce nes set time preventive maintenan is U pink not white pencil eraser t oxide from their contacts Thorou hl d uic deive cable have gold contacts erdser The extra careful when connecting and disconnecti H T t 2427 t n zhile working the vicinity of power ies Power power cord must di i wall Polarity MUST be rigidly observed e discohnected fromthe When removing and replacing drive and system e careful not to snag wires or short pins or test sis Particularly observe that the power lines going to and from the 120 VAC and power supply do not get pinched or rubbed by the enclo or by don t protect you from this saster Some drives and i Ing o be ystems sloppy power wir good practice after buttoning a system back up is to tinuity check between the disconnected 120 VAG plug s hot and neutral prongs to the equ
34. Other drives TANDONs use an alignment cam screw This slotted screw may be metal or peus and it occupies a metal or plastic oblong hole in the rear of the drive You should not confuse it with cam screw used to adjust the sensor in other drives because as as we know no drive uses a cam screw method for both Read Write head and sensor alignments T lignment cam screw uses a cam principle a large rotation is translated into a small linear displacement And the motor body is much greater in circumference than the linear travel of the head carriage assembly caused by rotating it Motor aligned drives are easier to align than cam aligned drives Using either method manual rotational movements are translated into much finer head linear displacements To align TANDON drives three module assembly screws must be loosened These permit movement of the entire module assembly during alignment These screws are covered with paint or loctite Two are ocated just to the rear of the large pully and one is located in the back of the drive near the alignment cam screw They require 7 64 allen wrench They should be loosened just looser than snug If you feel significant resistance or binding when aligning the drive you failed to adequately loosen a module or motor screw See Screws 1 2 and 3 in photo section In stepper motor aligned drives there are no separate module assembly screws To align them you must first loo
35. V QUME CORP zxbi2350Q epe gt San Jose 95131 MATCHLESS SYSTEMS 18444 5 Broadway Gardena CA 90248 MICROCOMPUTER TECHNOLOGY RADIO SHACK NATIONAL 1530 5 Sinclair St ii 900 E Northside Dr PARTS Anaheim 92806 im Fort Worth TX 76102 gt SHUGART ASSOCIATES gt Z ADDRESSES FLOPPY DRIES Euclid OH 44117 1 7 Sunnyvale 94086 pe i i 2054 1 MENS COR y 97 54 Deering Ave E P ars on them are manufactured by the firms E er 1 2445 4 ES below 5 list may not be complete Many firms Chatsworth 913 1 NS m 6 N ood Ave South mese eerte ees nii ii sies Belin NT 08830 purchase OEM drives from these manufacturers MITSUBISHI ELECTRONICS gt 2 Most drives no matter whose label actually ap MICRO PERIPHERALS INC m TANDON Corp and re package them under their own names 2200 W Artesia Blvd 9333 Oso Ave Compton CA 90220 l I Chatsworth 91311 5 PERCOM DATA CORP HEWLETT PACKARD I SSS e St ana aa sss gt x t RE oce PeR e 1000 Circle Blvd _ 211220 Pagemill Rd 733 Telegraph Rd Minneapolis MN 55440 Corvallis OR 87330 Dallas TX 75243 Montebelio 90640 INTERFACE INC PERSONAL MICROCO I
36. WRITING A BIT 8 lt AFTER CURRENT FLUX REVERSAL lt ss Pas 9 Z lt cw zc mn Load known good BASIC program into the computer from good aligned drive Do a LIST to observe that the program Loaded right Then Save the program to the bad drive under a new name Load the program under its new name Do a LIST to verify a correct LOAD by the bad drive Then do a LOAD and LIST with the bad drive Formatted diskette inserted into the good drive or vice versa If LOAD and LIST works fine with the bad drive diskette in the bad drive but doesn t work with it in the good drive then prob ably the only thing wrong with the drive is that it is out of alignment ALIGNMENT MECHANISMS SHUGART MPI TRS 80 Color Computer TEC SIEMENS etc drives are all aligned by turning the stepper motor to position the head s Look for stepper motor screws usually loctite or paint Coated Two methods are used In most drives the stepper motor body has a flange with slotted screw holes In other drives the stepper motor screws clamp down on a ring that fits into a groove on the motor body Loosening these screws permits the motor to rotate in the ring Some drives have a slot in the motor flange that Corresponds to two ridges in the drive frame A screwdriver blade is inserted between the ridges and into the flange slot By turning the screwdriver the motor 15 rotated CW or CC V
37. are others around you MECHANICAL METHODS i both intermittent and dead sys a with without thermal meth ds Y Mechanical methods consist of applying SEMTE res e otion shock or vibration to parts and to the C boards Um Don t use your finger hand 25 1 x a eae Dd IN handle to gently tap on ntl ressure to or move around the suspect parts and i cont Any functional or error changes pinpoint the Mechanical methods particularly useful to ot opens causec by poor solders and conductive bridges Some techniques ifying that I work on a totally dead system after veri he not caused something Sdn cc i i i turn it upsi bad connection pick the unit up tur ner i d vigorously but not violently shake it slapping A ate The last time my wife saw me doing this she arcastically stated You must be an engineer I then verify and firmi restore all connections reconnect it up turn power ON and see what happens This is crude and can be risky but it miraculously cured dead systems by dislodging solder balls splashes hairs burrs and loose screws H the equipment is heavy such as expansion interface you MUST be a physically strong person i iggling i hnique Frequent line wiggling is another excellent tec
38. check drive speed again If drive speed remained within tolerance the problem is due to an alignment Read Sensitivity clamping and or i i ly running Observe the large pully under ysteresis problem or from a computer problem ne mor 60 Hz line AC the outer pattern should sync pi 60 ligne pulsations ener Paste Sed i is adjusted to exactly i speed RE RPS when the applicable bar appears to be standing still due to the 60 Hz or 50 Hz stroboscopic effect Consumerlronics Co 2011 CRESCENT DR P DRAWER 537 ALAMOGORDO 88310 Figure illustrates PPL data recovery circuit using the Western Digital 1691 Floppy Support device Both Dt 528 data recovery and Write Precomp Logic is contained within the 1691 allowing low chip count and PLL re RAW _ __ 27 RAW READ liability The 748124 supplies the free running VCO FROM ORIVE as Output The PUMP UP and PUMP DOWN signals from SINGLE the 1691 used to contro the 7481245 frequer 9 DENSITY DOUBLE DENSITY FD179x CPU INTERFACE Xu WRITE 47 109K LL sans pr ep M ed ain mang oh EHE MC3887 1 4 wenrl 38 uS lt em SE ERRONEOUS WRITE OPERA J your drive s has erroneous lt WRITE operations on power up or power val 2 lt EL TR 34
39. con nectors the cable is unkeyed To select between 2 drive numbers or the 2 sides use a SPDT toggle switch To select between 3 or 4 drive numbers use a rotary Switch with 3 or amp throw positions Mini type switches should be used Disassembly usually requires only the removal of the drive en Closure One first locates a convenient position on the front panel of the drive and installs the switch there Be sure that the switch and its cabling won t interfere with the diskette and write protect notch detector The drive select jumpers header or dip switch are is then removed In common headers MX HL HM and HS shunts have to be separ ately jumpered in their previous positions In most drives the drive select IC socket contacts are 2 15 DS1 3 14 052 4 13 053 5 12 054 The lower contact numbers 2 5 are wired to connector Jl contacts Contact numbers 15 12 are togeth er and are wired to the logic board electronics Solder the J1 side contacts to the throw positions of the toggle or rotary switch Solder any logic board side contact 051 06 050 055 1 switch pole In DS drives generally 21 32 is used as the side select and 21 6 is DS4 In SS drives 21 32 may be used DS4 71 32 may separ ately jumpered to J1 6 in which case remove or cut this jumper With the drive in operation and your computer selecting Side 0 measure the voltage at 21 32 when the drive is selected In most
40. diskette may be A Contaminated Physically damaged Electrostatically damaged D Magnetically damaged and 0 are not visible A and B are Rotate the diskette within its shell and inspect for dirt grime dust oil scratches creases and discolorations under a good light If the problem is due to contamination dip a cotton Swab in alcohol and gently scrub the dirty area Allow to dry Try again n most cases this will eliminate the problem If the disk ette is physically damaged you may either wish to lock out the bad tracks if few not use the bad side or discard the diskette save the shell for a flippy conversion template Diskettes are manually rotated in the shell by gripping the inside of center hole between a finger and thumb and gently cotating the diskette s shell with the other hand 60 NON TECHNICAL TYPICAL DRIVE REPAIRS An analysis of drive repairs by the CASCIO School of Computer Technology shows that 60 of all drive repairs non technical Of the 80 technical repairs quired 20 were preventable 10 required only chip substitution while 10 required professional repair work Non technical repairs include cleaning connector contacts replacing defective cables cleaning and lubricating etc things almost anybody can do Technical repairs include alignment and adjustment electronic re pairs replacement of parts etc If you know enough to use good drive habits and take t
41. for repair that should cost 52 they ll gladly do it 1 the board or subsystem level swap doesn t solve the problem and it isn t due to something obvious they then usually the he interface or even the entire computer system at fault and charge you even more IV DIAGNOSTICS amp 0156 SERVICE MANUAL IH w TROUBLESHOOTING Uniess your time is very expensive be realistic how to repair your own equipment and make most Then if you still can t make a repair bring it to the shop If your system is still under warrantee then by all means avail yourself to the wasteful repair shop process unless time is at a premium and you can t get the repair done or a replacement in time Also consider by working on your own system you will probably void all applicable warrantees and unless you know what you re oing and are careful you may foul up things worse than they are now The decision and all of its risks and benefits are YOURS ALONE Don t admit to any shop that you worked on the equipment prior to bringing it in unless you obviously fouled it up because that s a green light for them to rip you off fot much more And once a shop has repaired your equipment ask for a complete description as to exactly what the problem was and what th ey did to repair it Keep good records DIAGNOSES Drive maintenance or repair is immediately required if the noise level of the drive significantly increases or changes
42. gt s 5 R Y HEAD 9010 8344325 20 ATMPAGSS Y Qv3H GIGS 3196 X399 _ YOLDANNOD iapter X DRIVE TEST STATION DISK SERVICE MANUAL III x he advanced disk drive repairman can build his own Drive Test tation to test all of the major drive functions and to align drives he output connector configuration of the circuit shown here is for scandard bus drives known standard bus drives use stan ard chassis and power supply connector For non standard bus 8 nd microfloppy drives refer to the drive s service OEM mainten nce manual for pin out of your logic control and power connectors Ve ve used our Drive Test Station to evaluate and repair over 100 irives he primary input signals to the Drive Test Station are the write sector index and read They all open collector outputs from the drive that require 150 IK ohm termina tion depending upon make in the Drive Test Station Read data and sector index signals are pulsed LEDs are used to provide ough indications of their presence recommend installing BNCs in the Drive Test Station so that these signals can be conveniently observed on an oscilloscope write protect LED is provided and will only activate if a write protected diskette is in the drive The TOO sensor LED is used to indicate stepping back to TOO The 5 VDC and 12 VDC drive power can be constructed from a s
43. has performed periodic maintenance over the years We mat the MTBFs specified by the manufactur y sales puffery The i 2022 12 y MTBF is supposed to represent MORE We wish you the best of luck We i cations programs and services COMPUTER AND ELECTRONIC PUBLICATIONS TUTORIAL DISK SERVICE MANUAL III PRINTER amp PLOTTER MADUN COMPUTER PHREAKING AB ITY CRYPTANA NIQUES SUPER RE INKING METHOD STOCKPRO Do ULTIMATE LOGIC PROBE HIGH VOLTAGE DEVICES HEAL THYSELF ELECTROMAGNETIC BRAINBLASTER THE GOLDFINGER THE SILKWOOD TELEPHONE RECORDER INTERFACE DECORDERS AND CONVERTERS etc These publications are des cribed on the back cover and along with our other mostly non controversial publications are described in our TECHNOLOGY SURYIVAL CATALOG You can order from the back cover or the catalog but the catalog is mostly recommended because it describ es our latest publications editions and prices Please send 1 fc cw TECHNOLOGY SURVIVAL CATALOG to the address val publications on electronics ener weapons securi i gence medical and financial You ay have heard te ek some of them on CBS 60 Minutes ABC Talkshows etc Please prod ol fot pe SUPER SURVIVAL CATALOG which describes nr Shocking and controversial publications to the SERVICES See our ad on the back cover for our TE RESEARCH SERVICES
44. in Parity or EDC type errors This problem is particularly prevalent in the inner higher bit density tracks Reliability is much in creased when a PLL Data Separator is used A PLL Data Separa DISK SERVICE MANUAL ITI tor dynamically ad the flow of Clock disadvantage with too man space must be allocated to Sector Headers and gaps justs the clock rate of the controller to match Data bits streaming off of the diskette The Sectors per track is too much diskette Disk drives have the worst trouble with the 6DB6 bit 6DB6 bit pattern is thus used as the FORMAT reliabi tern by most DOSs DISK ERROR CATEGORIES Disk errors can be categorized in two ways u Sector Header errors vs Data Field errors 2 Directory errors vs all other errors jattern The ity test pat diskette caused Sector Header mark DAM and EDC CRC or checksum errors are serious and either cannot be cor rected or corrected only by using sophisticated disk utility soft ware All errors in the first two Directory sector data fields and all user sector Data Field errors are generally easier to correct if you know the hash code algorithm or missing data The first two Directory sectors contain the GAT and HIT tables essentially con taining information that if lost can be recomputed from the other Directory entry sectors Damaged Directory file entry sectors are very difficult or impossible to correct the files referenc
45. is merely dirty it can be salvaged Some drive man ufacturers do not recommend the use of any solvent whatsoever to clean diskettes We have found that rubbing alcohol on cotton or a soft Q tip does an excellent job with no known damage to diskettes do not run while wet Rotate the diskette element inside its jacke while observing its surface in the Read Write Window The cont nation is usua visible Carefully rub it off or flick it off i 1cohol soaked Q tip MN asl en diskettes the worse contamination can be saved Read Disk DRIVE TUTORIAL in Recomme Chapter sure ations ipping diskettes labe the container Do not Fold Bend H Do nat X Ray Contains Magnetic Material OID MAGNETIC OR ELECTROSTATIC DAMAGE damage not place diskettes near magnets CR Ts telephones VAC power lines motors transformers relays buzzers bells speakers solenoids or switching power supplies or top of the keyboard Properly ground drives and work in a static free environment rmatting diskettes vigorously erase them one side at magnetic bulk eraser This refreshes and livens up their magnetic particles Diskettes have discrete shelf lives about five years For long term storage a cool dry and clean area is much preferred Aged diskettes shed their oxide coating stems specified otherwise do not leave diskettes in univer Unless they are being accessed except head lo
46. known to be separately available with no known substitutes If one of these fail you can t reasonably repair the board yourself Most newer drives have yPs which are usually also proprietary and which are more difficult to troubleshoot and a bear to unsolder 120 CURRENT LIMIT CUARENT SENSE INV INPUT NON INV IRPUT ndg v REES Tito cou TM 100 POWER SUPPLY TANDON NESI OTHERWISE SPECIFIED 1 ALL RESISTORS ARE 1 4 3 RESTOR VALUES N OMS Ke 1000 ZCAPACITOR VALUES IN MICROFARADS ANO WORKING VOLTAGE INDICATES CLOCKWISE ROTATION MCITZ3CP TOP Mew AMPS 45 VDC TYPICAL CURRENT REQUIREMENT MOTOR MOTOR DOOR START RUN CLOsED DISK DRIVE DC POWER REQUIREMENTS 5 READ STANDBY WRITE awan PM M AR I B o I Tia purpose of the end stop is to prevent the nead carriage assembly from bumping into the drive frame should for any reason ex failed maladjusted sensor unformatted diskette TOO is not detected The sensor output is combined with the stepper motor phases to determine when the head is at T00 For proper homing the sensor must switch somewhere between TOO and T02 Since 703 has the same stepper motor phases as 00 if it switches at the drive wil indicate 703 as TOO and may go insane If it doesn t switch by TOO the head carriage assem bly will conti
47. mechanism C Incorrect jumpering verify jumper block for drive head options D Low power supply E Bad connections internal or external i levels clean and lubricate the solenoid and mech EE slean all connectors and switch drives If that doesn t clear it up you either have a bad solenoid most likely or an electronic malfunction Solenoid reliability tends to deteriorate with age and use its pull strength diminishes with age whereas the electronics has a tendency to suddenly fail COMPLIANCE Compliance is a physical term used to describe how closely the Read Write head upon the diskette surface The major two causes of poor compliance are missin defective or misaligned felt pressure pad most common in SS rives or head loader if the drive has one drives if Head 1 is physically defective or grossly misa tigred compliance to Head 0 is also affected Field repair of poor D drive compliance is NOT recommended As compliance deteriorates Read and Write reliability decreases One fhe quickest ways to destroy compliance is to use a dry disk ette type head cleaner liance symptoms can also result from a worn head and ET or Write electronics If the head or electronics is at fault Read Sensitivity is generally low and uniform for all tracks If the problem is mechanical pressure and thus Read Sensitivity usually significantly varies between the inner and outer tracks Modern S
48. on the PC guide rail To swing the logic board away requires disconnecting the head connector s To remove the logic board requires disconnecting all other signal and power connections to it To remove the servo motor board entails disconnecting 2 connectors P20 P21 most drives and removing 2 screws the board is usually mounted on stand offs SPINDLE MOTOR Replacement of the spindle motor is also easy logic board is required in most drives Disconnect the motor Slip off the belt large pully first Remove the two mounting screws on the spindle side of the drive near the small motor pully and pull out the motor Install the new motor slip the belt back on reconnect the motor and replace the logic board The spindle motors used with almost drives that don t use a direct drive motor are identical and can be swapped between drives CONE MECHANISM Replacement of the cone assembly entails removal of both the logic board and the cone lever assembly in most drives The cone lever assembly is secured by two mountin Screws in the rear o 5 1 Removal of the The cone assembly consists of the plastic cone and u other small parts There are variations among drives Revove ihe E ring or retainer clip from the back of the cone lever assembly that secures the cone The cone assembly then comes apart Keep track of how the parts are assembled label them ar draw a pic ture Usually only the cone gets bad After thousands cl
49. other operations are OK you probably have index misalign ment blems reason for DRIVE DEVICE NOT AVAIL BLE type errors However before paralyzing panic sets in first check to verify that the drive is connected an turned ON that the diskette is inserted correctly that the drive s fuse is good that the drive s power supply is correct and that the DOS s drive configuration specifications ex PDRIVE are correct for that drive index optical coupler is usually sold as a pair The LED 2 share ihe same Panne tor ex P10 and they are fac tory matched If either the LED or sensor burns out and you don t have an oscilloscope to determine which one 809 of the its the LED then replace them both However test severa good diskettes verify their connection verify that neither has slipped out of its fixture and clean with alcohol Q tip and retest them before assuming that either is burned out A smudge or debris on either of them can cause havoc i i rive the hotosensor is located on the frame hub side of the drive t LED is located on the cone lever assembly Removal of both the logic board and cone lever assembly are required in most drives SEN THE MOUNTING SCREWS SECURING THE LED D SD DETECTOR FIXTURESI To do so requires re alignment when it is almost never needed In most drives the LED and sensor can be easily pushed out of their fixtures with a wood Q tip and the new ones pressed i
50. recommended fuses only Write head s felt pressure pad and the diskette face and wear them out as if they were rubbed wi 2 Never remove or replace enclosure or do any drive or s 3 Do not expose drives to extremes in tempe Cool temperature and low humidity are ideal ture should be 50 90 degrees F Changes in air pressure cause drives to breathe resulting in contamination Don t use drives as shelves for books and papers or enclose them where they can t ventilate They must freely vent heat Put at least 1 4 of space between standing drives for ventilation purposes We paste onto the cover sides of our free standing drives squares of 1 4 thick rubber Separation is maintained and the drives don t scratch each other when moved rature and humidity Ambient tempera 4 Don t expose drives to loud noises vibrations or shock Drives used near airports railroads major highways and industrial sites where noise and vibration levels are high experience very high fail ure rates High noise produces micro vibrations that rapidly deteri orate drives even when they are not being used Our drives rest on 1 2 thick dense foam rubber or cork cushions If necessar tern your drives in sound proof well ventilated and dust free closures 5 Avoid using drives in electrically noisy environments except with an AC voltage regulator power controller and proper AC DC neutral chassis ground an
51. sec tor index optical coupler and write protect detector opposite the originals Also requires electronically ORing the two photodetector outputs The exceptions here and ATARI drives that do NOT require and may not have installed the sector index optical coupler A description of how to modify these drives to is found in RADIO ELECTRONICS COMPUTER DIGEST July 1985 p 12 and does not require machining Essentially this can be done by connecting a 1 8K ohm resistor across the photo detector through a switch Whenever the switch is ON the drive will Write to any diskette whether the write pratect notch is Covered or not Therefore you can Write to either side of diskettes without punching write protect notches in them When the switch is OFF the write protect detector acts normally and the drive quires an open notch to Write 2 Shaving the inside stops to et extra tracks out of the drive normally made to convert 5 Tk drives to 40 Tk Consumertronics Co 2011 CRESCENT DR P O DRAWER 537 ALAMOGORDO NM 88310 te reet Fk wen asawa ii FRONT PANEL om 1 L SHUGART 5 851 SHUGART SA 851 8 DS 77 Tk 3 msec Split band actuated The 5 851 is identical to the SA 850 except that it is also compati ble to non IBM systems A modern popular ultra fast very relia ble 8 drive the SA 850 851 is hi
52. sooner than ones aligned to 95 100 symmetry because alignment errors start to show up at around 65 We average 85 90 symmetry just using our trial and error methods see alignment chapter Either most drive shops use their expensive equipment and software as eye wash only or they have a keen eye for future business When using a differential oscilloscope to measure misalignment the offtrack for 48 TPI drives in inches is computed to be OFFTRACK 1 15 lobe amplitude 2nd lobe amplitude X 0 01 1 1st lobe amplitude 2nd lobe amplitude refers to the CE pattern lobes the Offtrack by 2 For 96 TPI drives divide SCALE 50 CAT S EYE PATTERN INDEX TO DATA CE ALIGNMENT DISKETTE The CE alignment diskette is unformatted but contains two distinct types of signals the TOO databurst and the CE signal The 700 databurst or boot data simply permits the system to recognize the diskette as being compatible to the system thus permitting it to log It has 2 tracks with the CE patterns written in special locations a special drive Two concentric tracks of the align ment diskette cross at T16 or at T32 for 96 TPI drives or at T32 or T36 for 100 TPI drives 16 approximately half way between end stops 35 and 40 Track drives is used to judge head alignment DYSAN is the major source for alignment diskettes but th
53. spare drives J maintain or repair only one drive at a time If you make mistake you will still have a good drive availa ble to use as the boot drive to run your DOS I you must switch drives how you do it will depend upon whether or not you have a keyed gapped drive cable and whether or not you ve installed front panel switches see modifications chapter If keyed you must physically disconnect and remove the drives switch them over and reconnect them If the end drive is affected the TRN IC for the new end drive must be installed and the one installed in the former end drive be removed If the cable is not keyed all you need to do is switch the Drive Select DIP switch or jumpers on each affected drive accordingly Consumertronics 2011 CRESCENT DR P DRAWER 537 ALAMOGORDO NM 88310 Uw tI Verg pq qap DEDUCTIVE REASONING owners find life expensive enough without having to keep tore MES boards and a lot of parts on hand The owner must solve his problems in a more elegant fashion Also he usually can not afford to own sophisticated electronic gear nor has the time to learn how to properly use them However with little more than a good volt ohm meter logic probe and a lot of common sense ef fective troubleshooting can be easily performed i nalyze the nature of your problems Run through your Operations and carefully record all factors relati
54. th m due ios loose or dirty connector see above As com ompact thermal related ome more and more a Thermal problems be mechanical elec trical or electronic in nature ignifi hanical dimensional changes occur when lenges ed drive that is can i j arming u Ele iun poor Sol er joints carbon resist a el ctrolytic capacitors can open short or become intermit Sur wer h ated or cooled This problem is particularly bad in i ee ent and equipment with the history of large tempera aged poor storage overvoltages and or mechanica Poi and ibration Minute shifting of socket contacts and IC pins ae all the difference in the world between a good connec open And contacts and pins that are hot tend E dize p ticularly with age and humidity sometimes simply gt y ee a socketed part and pushing it back in resolves the prob lem i they slow down and output lower Ae LN removing cover from din subsystem can change temperatures sufficiently to the roblem until the cover is replaced If your system ut and consistently either malfunctions or straightens it S out as a function of equipment or room temperature and or ON time use these methods to ferret out the problems i i ith a spout for ircui ers in aerosol cans They come wit These coolants pand designed for e
55. the cam screw or motor body CCW about degree per move until you either hit an align ment area or you hit the stop on the other end If again you hit a stop repeat the CW movement Continue to go back and forth at least 20 times before giving up Don t get nervous or rushed Remember track to track radial distance is only 1 48 35 40 and 77 Track or 1 96 80 Track and in most correctable misalign f misalignment is only few thousandths ment cases the amount o of an inch NOTE DRIVES CANNOT BE ALIGNED BY SKIPPING TRACKS After tightening all your screws repeat DIR N ten times If errors are only occasional and CRC or Parity types then alignment 15 close Loosen the screws just enough to make a few minute ments to home in on the aligned position with finer adjustments Retighten the screws Then use the procedure described earlier to determine whether the drive is still out of Alignment bulk erase and re Format the bad drive diskette d drive diskette should now be Readable and Writable to the good drive and vice versa s is to keep the drive continu A better method is to do this Some DOSs can be configured to i Most The object of doing all these DIR N ously Reading as long possible using drive diagnostic software erform up to 255 Read attempts before an error is called Do an AUTO DIR N DIR OSs provide an AUTO function D iN DIR Every time RESET is hit an attempt
56. use today be classified into about a dozen distinctly different types If we don t mention your partic ular system or drive of the many types mentioned your drive type will be covered to the extent that you can service it If you want to become an expert on any particular drive you should also obtain its service maintenance OEM manual from its maker We gladly accept advice and information to improve DISK SER VICE MANUAL for its later printings and editions This includes drive service manuals books articles photos discarded drives and TRS 30 disk utility software We articularly seek articles and we will pay money and provide a by ine for those we can use All articles should be replete with labeled photos and illustrations We are also interested in drive modifications and all other secrets and tips For substantial information that we use in future printings and editions we will provide you copies of all future editions free of charge If you manufacture or distribute drives media or relat ed products we would like to evaluate your product s for future editions please send us a complimentary sample s or loaners We thank SHUGART TANDON BASF VERBATIM WESTERN DIGI TAL and many others for their invaluable thoughtful and consum et oriented contributions air broken disk drives for free CONSUMERTRONICS CO customers only who have ordered at least 20 in publications from us See our address herein We will fully
57. yy Virtually all index misalignments are corrected by adjusting the photosensor alone In most drives this can be done from the pully side of the drive just above or below the pully You ll find a phil lips mounting screw You ll also see slots in the frame and back of sensor fixture where the blade of a small screwdriver is placed to turn the fixture left and right do not adjust by moving the screw left and right In some drives these are inside a deep depression in others they are flush or flush with the wall Before ad justing the sensor loosen this screw to just loose of snug Adjust the sensor by turning the flat bladed screwdriver in the slots CW and CCW If the fixture does not move smoothly and easily slightly loosen the phillips screw a little more When the sensor is adjusted tighten the phillips screw a slight amount and retest If the sensor got out adjustment which commonly occurs re adjust it This the most aggravating of all drive alignments Tighten the phillips a little more and retest again Repeat this process until the index is aligned and the screw is just tight beyond snug CAUTION The LED and sensor fixtures are plastic too much torque can strip them out Finger torque on the screwdriver is usually adequate Since they are not subjected to significant stress their mounting screws are not likely to loosen and thus need not be real tight WRITE PROTECT DETECTOR The write protect sw
58. E GATE T MM DIRECTION 8 5 MIN WRITE DATA UA M MN 500 NS MIN STEP AA DIRECTION SELECT 3 ms MIN 5 18 ms MIN F a ms onm 500 ns MIN 1 MIN BIER TRACK 00 DETECT DENT 100 MIN 1 1 ms MIN 4 ms MIN pe SIDE SELECT T munt oce a Pe STEP TO READ SHUGART ASSOC WRITE TO STEP SHUGART ASSOC A DISK SERVICE MANUAL ITI HEAD 0 ERASE READ WRITE n eu P E P N ERASE 7543 V sa nee in N WRT N WRITE D Pon DATA gt 2464 3 ted 29404 m ar 1 Ae 740b m 2 24129 ELECTRONICS amp REPAIRS VIII 6 Plo INDEX PHOTO ASSY WRT PROTECT SWITCH S s N WRITE GATE NDS1 NDS2 NDS3 NDS4 N MOTOR 4 TRACK 00 Ta SWITCH zi Jl DIRECTION TANDON TM 1 SCHEMATIC 00 740 H6 1454 i m amp SYNC OUT 24 534 D N INDEX Lo N WRHE 74 534 PROTECT N ERASE D FRONT PANEL MOTOR ON MOTOR POWER MOTOR GND N TRACK 00 Y r n Chapter MISCELLANEOUS REPAIRS Prior to the removal or installation of the drive e
59. EMENS FDD 100 5 5 SS 40 Tk drive Lead screw actuated Primary positive features are its wide door opening and quiet opera tion Best access time has been 12 msec Quality is very good but we have had reliability problems due to low Read Sensitivity on both inner and outer tracks SIEMENS went out of drive produc tion and its drive facilities have been sold and resold SIEMENS type drives will probably reappear under other names MOTOR SCREWe DRIVE CONNECTOR LOGIC BOARD Mi AA ssp T MI cts CONSUMERTRONICS ATTN John J Williams MSEE 2011 Crescent Dr 537 Alamogordo NM 88310 SHUGART SA 400 SHUGART SA 400 5 SS SD 35 Tk drive Spiral wheel activated This slow primitive by today s standards drive is now being dump ed new for practically a song Not suitable to most modern comput er systems Avoid this drive It s not worth fooling with Definite ly limited to 35 Tk and probably to SD because of poor reliability in Formatting inner tracks at DD We repeatedly wrote SHUGART about ways to upgrade the SA 400 and as helpful as SHUGART has been with their other drives never responded disappointing con sidering the vast popularity this drive had in earlier days 7T e 2 TCH LS cmd 5 5 ud pa MET _ CONSUMERTRONICS ATTN John J Willi
60. ERVICE MANUAL andeor a Copy of the drive s service maintenance OEM manual I stri dics recommend that you work on your own drives using SOFTWARE produces DDA software for the KAYPRO Although we were unable to obtain and test their DDA software we found their documentation to be excellent very specific detailed and comprehensive with drive illustrations and photos DYMEK documentation is apparently very very skimpy e evaluated alignments and speed adjustments made using the described ir DISK SERVICE MANUAL with the 2 amp M soft ware All of our alignments were within the acceptable range except the accuracy may have been a little better if we had used the J amp M software and the J amp M software would have certainly been faster We made many alignments using the J amp M software It appears that if you get too far out of range the J amp M graph indicator freezes up and you can easily lose your place We also used the J M software to adjust speed and sector index photodetector alignment In one drive even though the soft ware indicated a perfect 300 RPM using the zebra pattern on the drive s pully under a fluorescent lamp we still detected a small drift Our optically coupled digital counter independently checked the fluorescent lamp frequency as 60 Hz 0 15 Also if your system has a speed modification clock speed up kit unless you can switch back to the designed in speed the J
61. FY DS DRIVES FOR DS 2 SS CONFIGURATION AND FORCED SIDE SELECTION nnt C tons es DRIVE MODIFICATIONS DISK SERVICE MANUAL III XIII 2 ration is easy By carefully labeling your switches you should noe be confused p which drives switched to which number and which side is selected The only danger is in switching a drive during an operation front panel LED lit which should never done If two drives are inadvertantly switched to the same drive number although neither will work until one is switched to another number no permanent hardware damage should occur KEYED CABLE MODIFICATIONS In keyed cables generally the J1 32 contact is missing in all drive connectors except the 4th one If you use 3 drives instead of 4 and the last drive is DS you can jumper the 32 ribbon cable line directly to J1 32 of your fast DS drive This permits your comput er to treat Side 1 of Drive 3 as Drive 4 To do this find and separate the 32 ribbon cable line and with an X ACTO knife carefully scrape off its insulation We then solder a 12 jumper to line 32 and another 12 jumper to the top of the drive s 21 32 contact Then solder a male connector pin to one jumper and female to the other We then connect the two jumpers together and wrap the connection with a short piece of electrical tape SS TO DS MODIFICATION Some drive repair shops claim that you can modify SS d
62. I _ __ __ ____ __ ____ ___ ___ __ _ _ __ TESTER EMULATOR This versatile and powerful circuit permits you to test TTL and CMOS ICs either in situ while under actual operation or out of the circuit One thumbwheel TW switch is required for each pin of the Zero Insertion Force ZIF socket B Each TW switch has six positions 0 5 0 Ground 1 V Pos 2 Clock Input Pos Output Pos 4 Pulse Input Pos 5 Corresponding ZIF Socket Pin C Circuitry of Pos 0 3 Note that while the ground V and Clock inputs go to all the corresponding TW switch position numbers each Pos 3 TW switch pin goes to its own Pos output display circuitry An alternative is to use XOR gates in the out puts to compare an in situ DUT to its Verifier IC Note also that the clock can either 10 Hz or iK Hz D Power supply wiring for both TTL and CMOS tests E Pulser circuit for Pos 4 for all TW Pos 4 pins bounce ree pulser output is ideal for simulating control voltages Each IC Test Clip pin is wired to its respective TW switch Pos 5 pin This TW switch position is only used when the DUT is in situ on the circuit board and is being compared with an identical and known good IC Verifier TW switches correspon ing to output pins are then switched to Pos 3 All other pins are switched Pos 5 The IC Tester Emulator can be used to test ANY 14 or 16 pin IC in ANY mode of c vat
63. In addition for a fee we will deum op and or build virtually any device you need Please describe to us exactly what you need designed developed and or built Please in clude non refundabie 525 so that we can spend the time to work up an outline and estimate for you Send to the address below Consumertronics Co 2011 CRESCENT DR P O DRAWER 537 ALAMOGORDO NM 88310 Don t fully understand how drives and diskettes with computer systems The numero uno source Bf phil ette theory and practical facts is DISK DRIVE TUTORIAL IL See the description of DISK DRIVE TUTORIAL H on the back cover SURVIVAL PUBLICATIONS We also publish 60 brutally frank survi Chapter Il JPERATION ADVICE amp TIPS DISKETTES DAMAGE not tear fold or distort upon them with hard object including pe 15 ball point pens and paper clips use a felt tip or get em ily or wet or expose them to temperature extremes sunlight ticrowaves x rays or infrared Do not use dirty bent creased or 9 4 the diskette s recording surface with fingers Hold iskettes at their rear Do not leave diskettes uncovered Do not tore diskettes horizontally or lay them on rough uneven or dirty urfaces or lay anything on top of them Do not use a writing aser on diskettes the debris produced is abrasive i not assume that an error prone diskette is bad diskette If m
64. NC TEXAS PERIPHERALS lo eil Milpitas Blvd 7630 Alabama Ave i 875 Ellis St 1010 East 8th St Milpitas CA 95035 Canoga Park 91304 Mountain View CA 94043 Odessa TX 79761 J amp SYSTEMS PROSOFT VR DATA DISAN es 437 Utah NE Dept 560 777 Henderson Blvd N 6 Santa Clara CA 95050 Albuquerque NM 87108 North Hollywood 91603 Folcraft 19032 DUT Device Under Test EDC Error Detection Code dcus an Inch 0 001 Inch EL Expansion Interface 1 EMI Electromagnetic Interference MIBE Meee e es 2001 Second AM Amplitude Modulation FCB File Control Block OEM Original Equipment BDOS or BIOS BASIC DOS Error Floppy Disk Controller OS Operating ent Manufacturer Twist On Coaxial Connector FM Standard Freq Mod Encoding SD AB epe I Modified FM Encoding DD 2 Board Also CA Computer Aided Modified Encoding DD Computer CAD CA Design 1 FRSN File Relative Sector Numbers PLL Phase Locked Loop Engineering RUE GAT Granule Allocation Table pot Potentiometer Variable Resistor CAM CA Manufacturing cca Group Code Recording RPM RPS Revolutions Per Minute Second CE Cat s Eye Alignment Pattern 277 1 HIT Hash Index Table DM SPDT Single Pole Double Throw Switch 2
65. S LTD 137 Albuquerque 87108 TRS 80s KAYPRO and SANYO 2 DYMEK CORP 1851 Zanker Rd San Jose 95112 IBM APPLE and TRS 80 3 VERBATIM 323 Soquel Way Sunnyvale 94086 APPLE and IBM SHEEPSHEAD SOFTWARE P O Box 586 Boonville CA 95415 KAYPRO 5 CHANDLER SOFTWARE 273 West Shore Dr Marblehead MA 01945 all CP M 2 2 and 3 1 systems 8 SS SD 6 BROMLEY ENGINEERING 333a Cambridge St Cambridge MA 01945 the HEATH ZENITH Z 100 5 and 8 apparently designed for repair shop use 7 A number of readers have highly recommended CSM CO s 1541 Disk Alignment program for their Commodores Address unknown GENERAL COMMENTS Mos ut not all microcomputer systems supported by DDA software If your system is not DDA supported you can overcome this problem if your system uses standard bus drives not any non supported system requiring a specially configured or proprietary drive and you can temporarily switch the drives to another standard bus computer that is DDA supported even if one system uses hard sectoring and the other uses soft sectoring Although drive problems produce exaggerated symptoms because of system related problems drives out of alignment adjustment in one system are out of alignment adjustment in all other systems they can be used in Other systems are DDA supported only to a limited extent due to one factor or a
66. S drives use felt pressure pads that have colored wear zones so that visual inspection alone is enough to determine whether or not the pad is wearing uniformly and or needs to be replaced A quick test to verify a felt pad caused compliance prob lem is to GENTLY apply finger pressure to the drive s upper arm of the head carriage assembly while the drive is operating Removal of the logic board and shield may be required to access it or apply t temporary gentle pressure with a long stem Q tip If drive ability substantially increases then the felt pressure pad is worn or misaligned it may be missing You can feel the pad when you clean it with a Q tip and you should know when it is gone After swinging away the logic board and carefully swinging away or removing the upper arm assembly 2 screws or nuts the felt pad is then peeled out of its recess in the upper arm using a pair of tweezers Carefully peel the new pad off of its self sticking paper backing and stick it into the pad recess Presto Re install the upper arm assembly Inspect how the felt pad situates above the head It should be centered precisely over the Read Write coils and its surface should be parallel with the head Then install the logic board Whether you replace the felt pad or not to obtain the best compli ance you may want to adjust it which you can do in one of two Ways 5 UNEVEN PAD WEAR Two set screws nuts secure the upper a
67. SE WRITE JER CLOCK DATA Rw COIL READ READ DATA ie IRCUIT wu ne WPN 1 iRCUIT BOARD READ WRITE CONTROL BOARD PACK RESISTOR ASSY WRITE PROTECT SENSOR DRIVE MOTOR ASSY UPPER PLATE ASSY EN 3 4 MBA Un DISK SERVICE MANURL III MISCELLANEOUS REPAIRS 5 gt gt pi gt M 6 lt zi nw o gus z 9 v lt 4 lt 4 5 a v w 4 X3 ONA N ARI Y N Mod EIGHT INCH DRIVE RM 55 J gt d m z z IRACK OO SENSOR ASSY MOTOR CONTROL BOARD N BAND ASSY 25 L 4 S TANDON TM55 2 4 AND TM50 1 2 FIVE IK ZH DRIVES WRITE PROTECI SWITCH ASSY OISKETIE LEVER ASSY INOEX SENSOR ASSY ORIVE BELT STEPPER MOTOR ASSY FRONT BEZEL ASSY i eH ER papas 331 X30Nt 0193130 10 3SvHd 60 8344315 8 3SYHd 20 9399315 38n NI iv 3SvHd 10 H3dd3 S IX 6 Oe DRIVE MOTOR 109957801535 AOv3H 80453130 00 NOVEL 21501 XION
68. a new PC ooo labor i spare hurting your feelings if they repaired to the parts level and charged you 400 for labor and 50 for parts This is bull because by temporary board substitution the problem can be isolated to a particular board Then an inspec tion of the board by an alert and experienced repair technician and some voltage checks usually quickly isolate the problem gown E the part in 90 of all cases The repair can be made and the original board restored all within one hour In 90 of all repairs not due to a event the total cost of the repair should not honestly be over 520 cam used by computer makers sometimes without field is to hide fuse s inside supply When this secret fuse blows the power atis in which case the shop usually replaces the entire unit e power supply is then returned to the factory they pop the cover off replace the fuse and resell it as a new unit i makers profit more from their and parts wei e thon they do selling the actual equipment Many purposely engineer in obsolescence time programmed defects special proprietary parts and repair booby traps to swindle you out of Hundreds of repair and replacement costs hat the profit margin repair shops but it must ras Keep in that most but not repair shops solely interested in the bottom line If they can no chargin you 200
69. ad Stepping is a strong indication of dirty or dry guide rails and less often of bad motor bearings Scraping sounds usual ly indicate a dirty head and or diskette Changes in drive Another good indicator of a dirty drive is diskette wear New scratches on diskettes call for immediate Cleaning of the head s and felt pad Make a habit of closely inspecting new diskettes be fore using them and after about 5 minutes of use Study the drive s Service maintenance OEM manual and DISK SERVICE MANUAL Where they might differ rely upon the manu facturer s manual Review al problems and error messages and record them and make a plan of attack PRIOR to the start of work Never do any maintenance or repair work on a bare hard sur face Mechanical shock can wreck a drive instantly Place the drive on a clean lint free and static free folded towel feit pad or Carpet pad We prefer padded vinyl covered toilet seat cover I usually work in my bare feet to prevent any kind of static build up The most important thing is not to lose your head If youa proach the problem in a careful systematic and logical way you ll likely solve your problem Treat it as a challenge and not as a chore Don t let it anger or frustrate you If you do have an unsolvable problem you may contact us for free advice Please describe your system and problem WRITE DO NOT PHONE US And please include 10 SASE If we can help you we ll respond Unless you have
70. aded drives that load the head during Motor On and do not turn the sys tem ON or OFF with diskettes inside Head and diskette wear ani diskette heat and contamination are the same for all diskettes system s drives whether or not being accessed u ly and correctly insert and remove diskettes from drives or insert diskettes in rotating drives with head load ers Drives with head loaders make clacking sound when either selected front panel LED is ON or upon Motor On spindle motor is turned ON The activated head loader solenoid causes the felt ad 55 or Head 1 DS to press onto the diskette surface opens ing the drive door wilt not disengage this contact in some head loaded drives Moving diskette in selected head loaded drive can severely damage r misalign the Read Write Head felt pres sure pad and or diskette WAYS ALWAYS back up important diskettes Ce three tier is preferred for critical diskettes MASTER 1 diskette Stored a safe refrigerator safety deposit box nly u Cop M COPY MASTERS 2 diskettes Only used to make Working Copies Stored away from Working Copies C WORKING COPIES 1 diskettes The only diskettes used in day to day operations Only new high sheen bulk erased diskettes are recommended for masters DISK DRIVES ke drink or eat around drives or use them in a dirty x environment a good policy for ALL comp
71. age assembly sticks when it tries to STEP Also some cheaper drives have guide rails that are not properly toleranced or polished and the head car riage assembly sticks even when properly lubricated 3 Dirty warped diskettes which snag the head when moves wrecking the diskette jostling the head head ce Dry diskette type head cleaners also snag the head particular ly the more delicate Head 1 DS drives 4 The gradual wearing away of the tight tolerances in the module assembly particularly between the guide raiis and the head i ssembiy S 9 Belecuve or worn E nue stepper motor d carriage assembly and inside the 5 r A eS hal Sonit nave a sensor particulary APPLEs and COMMODORES and drives in which the end stop is set too far in operate by doing a lot of bumping against the end stop This bumping shocks all of the components of the module assembly and much accelerates misalignments Constant bumping can liter ally beat the drive to death Some software protection schemes rely heavily upon bumping in their protection scheme and bad R W COIL LT SIDE 0 READ WRITE HEAD WIRING DOUBLE SIDED DRIVE 5102 1 oe itn tenn tien att ese maby DISK SERVICE MANUAL ITI R W HEAD ALIGNMENT Vll 2 data blocks cause bumping in APPLE and
72. amp ing and turning actions particularly if abusive it gets worn dis torted or broken causing eccentricity problems Replace the cone mechanism and lever assembly in the r order of removal Be sure that the door is installed right Before tightening the mounting screws on the cone lever assembly insert a diskette into the drive and close the door Gently manuall Clamp the diskette then tighten the mounting screws SPINDLE ASSEMBLY Replacement of the spindle assembly is more difficult It should only be attempted IF the drive allows for its you detect wobbling or Binding in the pully when you turn it by hand no ette lubrication doesn t h irive indi pelt See n t help AND the drive indicates Substantial variations exist between drives screw secures the spindle to the pully In others th punched out please donate the drive to us for spare cud is Replacement of the spindle assembly is more difficult It should only be attempted IF the drive allows for its replacement you detect wobbling or binding in the pully when you turn it by hand no belt no diskette lubrication d t ive indi iud doesn t help AND the drive indicates In some drives a Substantial variations exist between drives screw secures the spindle to the pully be punched out please donate the drive t In some drives a In others the spindle must us for spare parts Both the logic board and the
73. ams MSEE 2011 Crescent Dr P O 537 Alamogordo NM 88310 APPLE DRIVE APPLE DRIVE 5 55 35 Tk Spiral wheel actuated Note that construction 15 very similar to the SHUGART SA amp 00 This should give you a clue as to its capabilities and qualities in respect to state of the art drives APPLE supplies its Logic Board which it calls an Analog Board A ease rn poe dens tere 9253 DRIVE COMMODORE DRIVE 5 SS 34 Tk Band actuated The 34 Tk is the limitation of the COMMODORE system not the disk drive The drive shown is a 1550 drive NE with the 1551 ROM upgrade installed ES Note that COMMODORE drives actual ly 5 themselves fully loaded with CPU OM RAM and Controller The drive shown is an ALPS drive COMMODORE also uses NEWTRONICS drives Both use the same COMMODORE Logic Board And E both are similarly constructed and actuat ed Major differences are in the door mechanism and Servo Motor Board In NEWTRONI rives the Servo Motor Board with the Speed is locat ust in front of the Drive Motor ALPS ves use a flip out type door NEWTRONICS drives use a rotated latch mechanism Dif M ferences in circuitry between the 1550 and 1541 has the 1581 Controller and RAM con solidated into large chips COMMODORE and ATARI drives are sim ilar Bo
74. ation to anyone you reasonably believe will infringe our copyright FOR INFORMATION LEADING TO THE CONVICTION OF A COPYRIGHT INFRINGER S OR TO AN OUT OF COURT SETTLEMENT WE WILL REWARD YOU WITH 10x OF OUR AWARD OR SETTLEMENT 10 MINIMUM This reward is limited to one 1 per case In cases of duplicate information only the person who provides the most substantial and earliest proof will receive the award This offer applies to this and all other CONSUMERTRONICS CO copyrighted publications DISK SERVICE MANUAL Chapter GENERAL fhru the years we ve purchased many floppy disk drives some ised We discovered that professional drive shops are expensive time consuming and a hassle We now do all of our own repairs ad ustments and maintenance time and parts permitting without special equipment or software We ve published survival publica tions for more than decade 80 and we practice the self sutf ficiency that we preach We may be old fashioned but we believe that if you want to do the job right in many cases you ve got to do the job yourself Due to the enormous amount of information available on disk drives and diskettes if being thorough is defined as covering everything known about a subject one would require an encyclopedia here We tried to be as reasonably thorough and comprehensive as possi ble Despite the hundreds of different computer and disk drive models 92 of disk drives in
75. ave in creased your drive memory storage capacity by a factor of almost 16 if the origi nal drive was 35 Tk SS SD or by a factor of four if the original drive was 40 Tk DS DD NOTE Since diskette directories occupy one full track with most sys tems regardless of the number of tracks densities and sometimes sides used cives with larger track numbers densities and sides have a greater percentage of sectors allocated for data than for directory TEAC 55F 5 DS 80 Tk half height drive Split band actuated The TEAC 55 has most of the features that the SA 465 has except that clamping occurs at slight angle Also the actuator is not under spring tension therefore the TEAC 55F is more noisy Also some drives are significantly more noisy than others Why We ve had no significant problems with ours TEAC 55 is now der 100 a very good ced BASF 6106 BASF 6106 5 SS amp 0 Tk drive Spiral wheel actuated Never had a problem with this drive type Press in press out spring loaded door is a negative feature We don t like the Sector Index LED epoxied to the Logic Board If it fails you ve got a BIG probiem We also don t like the drive connector to be in the middle of the Logic Board rear and the power connector to be in the center of the Logic Board because both odd ball locations prevent interchangeability with bus extender cards and some power supplies NO GROUND TAB SHIELD eg tremens fe em eem
76. cate when to clean and lubricate your drives The Read Sensitivity test is a powerful tool to detect deteriorated Compii ance caused by worn felt pressure pad misaligned upper a sembly worn head bad head loader and failing electronics S DISADVANTAGES 1 Although the J amp M diskette can be b ili such as HYPERZAP and has a hub ring the DYSAN DDD goes NOT have a hub ring Like CE diskettes it can ecause it i i i speciai procedures It is created by a special drive using t s risky to put ANY diskette in ANY suspect drive i the head wiring or write protect and write defective What if the drive due to mechanical failure head defect loves to eat diskettes ex burr on the head defective cone loose part your DYSAN DDD diskette is gestr youre 5555 tirne The clamping used by some drives ill di diskette center holes that is why Pub ve Dd overwhelmingly used Once distorted the diskette cannot be pro on ly clamped and it rotates eccentrically This is particular pU tating in an alignment DDD diskette where alignment Precision i extremely critical Because DYSAN doesn t install hub rings in their diskettes you either must accept a much shorter lifetime for them or take the chance of installing the hub ring yourself which they warn against Frankly consider the lack of the hub ring in the DYSAN DDD to be an importa
77. cause Soft WRITE Errors but are more severe ii 1 um m WRITE errors occur when data is incorrectly Written to the disk ette They are detected by using VERIFY VERIFY Reads the bytes just Written to the diskette and Verifies that they match the FDC Under some circumstances WRITE error message can result from a READ error during a VERIFY after the WRITE Try READ operations that do not entail a WRITE to verify that the error is due to a bad WRITE not a bad READ BDOS ERRORS The catch all disk error message used in CP M systems is the BDOS BASIC DOS error The BDOS flags several types of system Some relate to user errors others to format errors usually errors EDC The worse possible BDOS error is one indicating that a sector can t be found or correctly Read or the expected 10 Field sector track or side number cannot be found These errors indi cate diskette or drive failure or more seldomly a DOS or ap plications software bug Most BDOS errors occur during a READ If one occurs during a WRITE it is probably due to a READ error resulting from the FDC Reading the sought ID Field Sector Header before it can Write user data into the Data Field and finding an ID Field EDC error Or because the selected drive is not READY Or after a failed VERI FY Read after Write In the lab bit densities are around 70 000 flux reversals per inch while repetition rates exce
78. ce See 1 above G See 1 1 above Bad Stepper Motor Electronics Verify Write Enable Drive Select 5 NO READ A Controller Malfunction Drive Select B Head s And Or 700 Sensor Misalignment and miscellaneous repairs chapters C Head s Disconnected Verify connection to head s P5 P6 D Defective Head s Replace head s or module assembly E Defective Logic Replace or repair logic board F Poor Compliance See 1 H above See 1 D above ME H Data Separation Error Prone Upper Tracks Repair or replace controiler or FDC Isolate drive cable from noise reroute 6 FRONT PANEL LED INOPERATIVE Interface Not Enabled Verify Drive Select and other jumper configurations LED Disconnected Verify front panel LED connection P9 C LED Defective Replace front panel LED D Bad LED Electronics Replace or repair logic board 7 NO T00 SENSOR INDICATION A Defective SEEK See 3 above _ TOO Sensor Disconnected Verify TOO sensor connection P11 TOO Sensor Maladjusted Adjust TOO sensor D Defective TOO Sensor Replace 700 sensor Assembly E Bad 700 Electronics Replace or repair logic board F 00 End Stop In Too Far Adjust TOO end stop Verify Write Enable OFF and See alignment APPLE DRIVE SIA A 5 rho 7 ALL switches 965 3 CO PIN F
79. ck ON and retest the drive Although a good drive diagnostic softw i 3 k to test like PT DOCTOR is hig ghness and ef iciency that drive t After all head alignments recheck th ts end stop and sensor 5 case both will have to be readjusted T00 SENSOR amp END STOP Adjustment of the sensor outward should always b tet 1 verification and necessary an adjustment eee sensor adjustment is ALWAYS follwed by a radial alignment Fortunately neither the sensor nor end sto j 1 p ever gets out of adjust ment in most drives The singularly greatest why they get out of adjustment is because some do it yourself types love to ad just things when they don t need to adjusted if it works don t READ WRITE FACTORS DRIVETEC Noise Tolerance One Haif Amplitude Remaining Signal Signal Erased Erase Crosstalk Disk Clamping Eccentricity Multiple disk Insertions Positioner Backlash Mysteresis 3 Drive Head NN 1 ji 1 77 Track Alignment 0002 2 v Ll Read Write Ps Read Write Rewrite Reread Drive Speed 2 based on 20 revolutions fix it However on rare occasi i y v 1015 either have to ad j I f bef R Wri fail ure or physical shock Both the the sensor and the end sto j r op adjustment scre
80. d DC ground wiring See electronics chapter 6 To ship drives carefully package them so that they are fully rotected from moisture shock and vibration Particularly with S drives do not ship with a diskette enclosed but with a thin cardstock cut in the shape of a diskette the only cut out is the cen ter hub hole Ship with a desiccant Also drives that have flip out doors TANDON SHUGART etc must have their doors secured Either tape the doors shut or use a folded piece of cardstock wedged into the front panel door grooves Some drives with spring loaded doors SA 851 provide for screwing down the cone lever assembly to the drive wall 7 Store drives a plastic bag with air squeezed out and enclose desiccant To use long stored drive clean it if necessary and relubricate it 8 In finishing alignments and adjustments tighten 4 40 and 2 56 screws small threaded parts and all screws threaded into plastic ex front panel screws to 20 inch ounces of torque or less Do NOT overtighten or cross thread Except for alignment and 700 cam screws finger nail polish is usually a good means of prevent k te s a 0 Chapter l dec OPERATION ADVICE amp TIPS DISKETTES 1 TO AVOID PHYSICAL DAMAGE Do not tear fold or distort diskettes or impress upon them with any hard object including pen cils ball point pens and
81. d it for years without any problem Its spray nozzle permits surer and easier dispensation in hard to reach spots such as behind the large pully and through the holes we ve made in the glassine window in TANDON drives It is an acceptable lubricant if ambient temperature is below 60 degrees However WD 50 and 3 IN 1 oils do tend to dry out particularly in hot and dry climates and should not be used if you schedule drive maintenance more than 6 months apart DISK SERVICE MANUAL v One expert recommends BREAK FREE CLP a tefjon based lubri cant made by SAN BAR CORP P O Box 11737 Santa Ana CA 92711 Another expert recommends CHEMTRONICS CHEM OIL and MARVEL S MYSTERY OIL auto supply stores great for cars too We also recommend the hypodermically dispensed based ARCHER s Prec sion RADIO SHACK SINGER Sewing Machine Oil and WHITE Sewing Machine Motor Lubricant SINGER CAUTION NEVER lubricate plastic moving parts with petroleum based oils as the oil will dissolve soften or warp the plastic We recommend vegetable fish or baby oil OTHER CHEMICALS If your PC edge connectors are not and tend to tarnish we highly recommend CRAMOLIN OLD COLONY SOUND LAB P 243 Peterborough NH 03458 CRAMOLIN comes in two solutions One removes the oxides from the contacts and the other coats the contacts with an extremely thin protective film We are very pleased with CRAMOLIN Fo
82. diagnose your drive s H we can fix it we will fix it and ship it back to you we can t reasonably fix your drive s we will still return it to you In either case all you pay is shipping and insurance costs both ways We are providing you this FREE service because we want to repair as many disk drives as we can to increase our expertise in this area We benefit because we later sell this expertise in new printings and editions of DISK SERVICE MANUAL You benefit because if we can reasonably repair your drives your Cost will be much less than if you sent them to a repair shop And we ll not only caringly re air vour drives on a timely basis but also clean and lubricate them or FREE Sorry we do NOT sell drive parts or subassemblies NOTE BEFORE SHIPPING US YOUR DRIVES YOU MUST FIRST OBTAIN OUR WRITTEN TO SHIP THEM TO DO THAT PLEASE SEND US A DESCRIPTION OF 1 DRIVE AND COM PUTER MODELS INVOLVED 2 SYMPTOMS AND OR ERROR MESSAGES Send us bare drives and if possible include the drive power supply and any manuals Please do NOT send us your comput er Also we will gladly accept all donations of drives parts man uals etc PLEASE DO NOT PHONE USI For all inquiries please send us note and please be sure to enclose a 10 SASE We will write you back with the new address or information IF we have it else we can t provide it to you Floppy disk drives made by TANDON RADIO SHACK and TEXAS PERIPHERALS are v
83. drive select and drive side These mods have the following advantages 1 Save much time keying in COPY BACKUP and FORMAT Commands 7 2 Save much wear and tear on drive doors and cones Very useful when one does a lot of COPY BACKUP and FORMAT because the diskettes do not have to be physically transferred from to drive 3 Permit quick temporary changes in drive configuration Parameters without re entering the change into the DOS DISK SERVICE MANUAL III XIII 1 4 Very useful in performing drive repairs beca dri can be arbitrarily choosen as the boot drive din 5 Permits one to disconnect a suddenly defective drive without having to turn off the system or the drive These mods are simple carefree and safe All active lines to and from drives and computers are open collector You cannot damage either drive or computer electronic components by accidentally selecting two drives as the same drive number although you won t be able to Read or Write to them while configured this way Also since the TRN is generally placed in the drive physically Jocated furthest from the system on the drive cable it is irrelevant as to what the drive s number is and unless a drive is physically Switched to or from the furthest cable connector the TRN does not have to be changed This mod requires an ungapped unkeyed drive cable Look at all drive connectors If all contacts are present in all drive cable
84. drives can be selected either 300 RPM or 360 RPM ex SHUGART SA 475 The 360 RPM option permits them to use the 3 format for compatible data transferal from the increasingly unpopular 8 systems Most microfloppies use the 5 standard few SONY use a 600 RPM 10 RPS speed for increased data storage Always turn OFF power before removing or installing the drive e osure Always verify that all connectors are firmly and square ated before turning power ON CONTROL CIRCUITRY In some drives smaller servo motor board contains the motor electronics in others this circuitry is on the logic board Servo motor boards are located either in the rear of the drive or on the drive s pully side Some drives have a speed pot However newer drives do not and if drive speed gets out of adjustment you may have to replace or repair the affected circuitry or the drive itself Most drives use a proprietary that controls the motor speed This part is called a Linear Ana og Servo No common substitute is available it is not known to be separately sold and it is the most critical part in the motor speed control electronics Ideal drive speed 15 within 0 33 of rated speed Some systems will tolerate speed out of adjustment exceeding 1 In drives that don t have a speed pot and drive speed is greater than 2 out of adjustment or is causing problems you nave the choices of either replacing the speed control electronics which ca
85. e generally pos sible drives with solenoid head loaders only Head loading upon A Drive sel 5 B Motor On HM 25 Head loading may depend upon activity LED activation in some drives 5 MOTOR ON ACTIVATION Motor On will always occur com puter command Some drives also permit activation of motor On w a diskette is either inserted or removed from the drive high ly ecommended JS Motor On may depend upon activity LED ML 25 and or head loading options in some drives JSing motor On also depends upon whether or not the system sends motor On commands motor On commands are sent by the IBM PC and most of its compatibles and clones and motor On must be JSed to each drive s drive select 6 AUTOMATIC RECALIBRATION TO 700 Automatic Recalibra tion to TOO for each time the drive is selected may be chosen RE 55 Although this results in better track alignment it also pro duces more drive wear and tear and is time consuming 7 WRITE PROTECT SELECTION The write protect function is totally hardware controlled inside the drive 2 drives are tradi tionally write protected by covering the write protect notch 8 drives write protect is traditionally the opposite Some modern floppies will permit a JS selection of either method EXTERNAL SWITCH MODIFICATIONS Some folks modify their drives by the installation of toggle or rotary switch es on the drive s front panel These mods permit the HARDWARE selection of
86. e rock steady at the Vcc supply voltage Also all pins n directly connected to either ground or Vcc are input output cloc and control pins some control pins may be purposely pegged ground or Vcc check for a direct connection Also look out for stuck input output clock or control pin hard DC voltage less than 0 7 volts usually indicates a short to ground hard DC volt age within 0 5 volts of Vcc usually indicates a short to Vcc IC EMULATOR If all else fails you can use an emulator to ferret out malfunc tioning chips An emulator consists of a dip clip test clip con nected to a PC board consisting of a socket a quad dual input ex lusive OR gate 7486 and LEDs 10 The socket holds an identi cal type as the DUT socket pins are wired directly to the test clip s contacts that correspond to the DUT pins EXCEPT DUT outputs Outputs are wired to exclusive OR inputs The socketed outputs are wired to the other corresponding exclusive OR inputs which outputs are wired thru 1K ohm resistors to the LEDs The circuit is powered If the DUT is good its outputs will be identical to its socketed counterpart s and no LED will light If the DUT is bad one or more LEDs will light You don t need to build an IC Emulator for each IC type One with programmable socket pins will accommodate 100s of part types SUBTLE TIMING This is the most difficult method of circuit diagnosis and should only be
87. ead carriage assembly and the stepper motor Do not attempt this replacement without the maker s service maintenance OEM manual OTHER ADJUSTMENTS Modern 8 drives and some others may require special and Complex procedures not described herein These procedures differ between drive models and usually require special tools and guages They include precise head load mechanism adjustments head pene tration adjustments microfine head ee drives above 100 These special procedures should only be performed by a equipped shop using the procedures described in the indi vidual drive service manual SPIRAL WHEEL ACTUATOR ACTUATOR CAM se STEPPER MOTOR SHAFT CARRIAGE LIMITER HEAD CARRIAGE ASSEMBLY HEAD INNER HIGH TRACK ADJUSTMENT The inner track stop of SHUGART 400 and APPLE drives Screw to loosen to make the adjustment Adjust to 0 020 use feeler guage between the top of the Carriage Limiter and the Step and between it and the Motor Shaft FRONT PANEL LEDS and B show the proper procedure for removing front panel LEDs activity lamps and show the proper procedure for re installing them 7 N ED 9 ag s TWO HUB By sort TYPES REPLACEABLE NON REPLACEABLE HUB ASSEMBLY HUB ASSEMBLY DISK SERVICE MANUAL III MISCELLANEOUS REPAIRS CONE AND DOOR DISASSEMBLIES TANDON IX 3 gj 8 lt REL 3 1 SPRINASE
88. eated Then turn system power ON Allow drive and system elec tronics to warm On either side of the drive both sides DS drives in about the center of the drive one can see the drive head carriage assembly It may be visible inside a compartment with a glassine cover PWOT LEVER TOO SENSOR SHUGART ASSOC fon Et a veter ew eim em imm ie ien DISK SERVICE MANUAL III Vil 3 DON Don t remove this cover for alignment purposes not involving loose collar Most drives are easier to access to align if the drive module is physically separated from its power supply The logic and servo motor boards do not have to be removed the alignment cam screw or stepper motor tip pen or scratch awl to mark the initial To align a drive using t that you don t lose sight FIRST use a fine fe position of the cam screw motor body so of your start point Format a diskette with a good accurately aligned drive Do some DIR Ns which should be OK N drive number Then insert it into the bad drive Do some DIR If errors continue adjust the motor body or cam screw pos tion about degree CW Do some DIR Ns Repeat the CW adjustment and DIR N procedure until good DIR N occurs If you get one with a different color fine felt tip pen mark the motor or cam screw position with a fine line Continue adjusting CW about 1 degree each time until the good DIR Ns s
89. ed 15 MHz The output of the Read Write Head is in fact a high frequency carrier Noise bit drop outs zone dropouts and periodic and random amplitude modulations AM and bit shifting result in a complex error roblem For more information on drive design problems see EDN April 5 1988 175 ERROR MESSAGES The following are common type disk related errors with some common variations Since there are some differences between the many computer systems they may not be identical to the error messages of your system but should be at least similar In some systems errors given in terms of error codes and one must use a look up table or type in a command to obtain the actual error message DISK DIRECTORY TYPE ERRORS 1 DIRECTORY READ WRITE ERROR An error resulted dur ing a Directory sector READ WRITE 2 ILLEGAL LOGICAL FILE NUMBER The File Control Block the Directory contains bad data 3 READ WRITE ERROR error resulted during Directory GAT sector READ WRITE DISK DIRECTOR Y TYPE ERRORS 1 DIRECTORY READ WRITE ERROR during a Directory sector READ WRITE 2 ILLEGAL LOGICAL FILE NUMBER The File Control Block FCB in the Directory contains bad data 3 GAT READ WRITE ERROR An error resulted during a Directory GAT sector READ WRITE 4 HIT READ WRITE ERROR Directory HIT sector READ WRITE 5 FILE or PROGRAM NOT IN DIRECTORY Your program tried to open a non e
90. ed Pot etc We wrote all of the major drive manufacturers at least five times requesting loaner drives and manuals for DISK SERVICE MANUAL Most never responded SHUGART by far provided the most co operation It is no coincidence that most of the finest drives manufactured are SHUGART drives You can t go wrong with SHUGART It stands to reason that if your product is state of the art and of exceptionally high quality you welcome evalua tion of it by independent experts We welcome all drive manufacturers to provide us loaner drives and manuals to evaluate and photograph for future editions of DISK SERVICE MANUAL and DISK DRIVE TUTORIAL We welcome all diskette manufacturers to provide samples for DISK DRIVE TUTORIAL 5 ruan PILAE aysana 1 Sakaq ai CONTROL DATA 8330 CONTROL DATA 8330 5 DS 80 Tk drive must be considered the e F Cadillac of 5 drives at least mechanically Split band actuated with a rather heavy well designed and impressive R W Head Mo E vL dule Never had a problem with them Ug 5 gt ues P i 58 7 uz 25 p J P IST usss Bebe SX COPYRIGHT 1985 JOHN J WILLIAMS amp FAMILY ALL RIGHTS RESERVED By John J Williams MSEE CONSUMERTRONICS CO
91. ed by them will no longer be accessible an error occurs in Sector Header EDC b enerates an immediate interrupt termination foc error results An error in the Data EDC will produce a DATA EDC error message If the error 15 in the DAM it cannot be recon structed and the sector is lost the controller interrupts the instant it sees an unauthorized DAM resulting DATA RECORD NOT FOUND type error during a READ or WRITE SEEK ERRORS A SEEK Error occurs when the track add a SEEK is not the same as the track ad The most common causes are head mi eccentricity clamping yte the controller and a Parity or ress Read by the FDC after dress expected by the FDC salignment hysteresis and When a sector becomes totally lost pected track or sector information aft the controller finds unex er a SEEK operation from misalignment or a damaged diskette a SEEK error will be dis played during a READ WRITE Hardware SEEK errors can sometimes be corrected b the Read Write Head back to TOO to recalibrate its position and or by re clamping the diskette If not either the Read Write Head and or TOO Sensor must be re aligned and or the spindle and or clamp assembly replaced or the drive discarded READ ERRORS READ or DIR errors occur when t data previously Written on a diskette does not match the EDC values stored in the Sector Header READ and WRITE errors are mostly caused by a defective diskette
92. els Proper VAC maintenance usually re quires a regulated VAC supply With DC voltmeter and the drive turned ON carefully check all VDC voltages with respect to DC ground Unless they are within 55 of rated voltage carefully adjust the voltages to these ideals if possible For power supply related problems see diagnostics and troubleshooting chapter TROUBLESHOOTING Only about 10 of drive problems are due to electronic failure Alignment clamping hysteresis and 00 end stop problems are solely mechanical in nature Drive speed and Read Sensitivity prob lems are mechanical about 90 of the time TOO sensor index optical coupler write protect and head loader problems are mechanical about 505 the time See chapter on diagnostics and troubleshooting Turn OFF drive power before removing or installing its enclosure Verify all con nections prior to turning drive power ON and turn power ON only as required NEVER CONNECT OR DISCONNECT THE HEAD CONNECTOR S WITH POWER H _ vubleshooting of the logic or servo motor board is required and you are not clear as to the wiring of your drive s board you should first obtain a copy of your drive s service or OEM manual NOTE Since many drive models go through several circuit design changes the actual wiring of your drive s Circuitry may substantially differ from the manual s schematic To inspect for electronic defects run the drive until warm Remove its enclosure Visually
93. ems 1 If the end stop is set in too close or the sensor is broken repeated bumping into the end stop will be heard during boots as the head carriage assembly continually tries to trip the sensor 2 The danger of setting the end stop too far back is that if the sensor ever fails the head carriage assembly may hit it with such force as to wreck or misalign it 3 If the sensor is set too far in the head won t Read TOO as it normally does immediately following a reset by the sensor of another drive s diskette Instead it will land on another track and get lost Although the drive may not be able to Read other disk ettes unlike head misalignment problems the converse is not usual ly true If you bulk erase a diskette and Format with such drive it will probably be Readable by other drives Also the drive will not be able to format the number of tracks indigenous to that drive To verify misalignment first clean and lubricate the bad drive Then adjust the spindle speed of both the bad drive and good drive to its proper speed see speed adjustment chapter Then take a magnetic bulk erased diskette Format it with the bad drive label it so it won t get mixed up DISKETTE MOTION t 4 OXIDE SURFACE MYLAR WRITING BEFORE CURRENT FLUX REVERSAL RECOROED BIT READING A BIT FLUX REVERSAL IN RING GAP CURRENT aq lt 0 RECORDED 9 d
94. ents ti tighten 4 4 screws small threaded parts and all screws threaded Bo ex front panel screws to 20 inch ounces of torque or less Do NOT overtighten or cross thread Except for alignment and 100 cam screws finger nail polish is usually a good means of prevent ll 1 m nnm a M az PPNO TE E E EEE OOIE OE TEE E O EEEE RN TTD Chapter ERROR MESSAGES ERROR MODES amp RECOVERIES i ccur 99 9 class average may put you a class but you would fail miserably as a ave error out of 50 000 bits can ruin very expensive progra file i itivities Before tossing away Different drives have different sensitivities at di te or using a disk utility to rep try Read drives ane at different times Temperature humidity level and line noise and previous operation ir current operation sometimes enough to a p y Readable diskette Readable and vice versa inimize disk errors During i efforts are taken to minimize are locked EDC codes ino the ID and Data fields to Verify accuracies Man 5 possible but the two main ones CRC and checksums i i d produces a i up all the bytes in a field and p bore Each recorded check byte d compared Ui in mput uring a R w
95. error Pesults this division yields a zero remainder EDN Y 1 5 he 28 1978 p 129 for greater details on gaps t Pc and controller unctions and BYTE Sept for greater CRC details RADIO E MORROW EAGLE and DATAPOINT microcomputers use EDCs ERROR SOURCES i i as it MEDIA If the diskette is warped AM ite head If the oxide coating is inconsistent AM also occurs due to changing Ha shat 1 ugh zone dropouts also occur 1 3 oxide contains pits scratches or impurity bit and zone dropouts result If the oxide is rough bit dropouts and noise result Surface sheen is important E HEAD dirty head results in zone dropouts stay the same lessen as the head steps in 206 out Drive speed variations head Sector Index a s misalignments can put the head in the wrong piace ar me wron time The aerodynamic design the head is also imp poor AM results as the head skips across the diskette surface FORMAT VARIATIONS ed diskettes Formatted machine language number of sectors per track and sectors per gran Rind the number can be varied per track The encoding scheme can also be varied with DD and SD sectors even appearing on the same track The risk of too few sectors per track 1s that the controller can get lost due to small variations in diskette speed resulting
96. ery Similar in their design and construction Uniess stated otherwise maintenance and repair comments about TANDON drives also relate to RADIO SHACK and TEXAS PERI PHERALS DRIVES The terms drive and diskette denote floppy disk drive and flop disk ette respectively The term 5 rive is shorthand here 5 25 disk drive acronyms SS DS SD DD and QD denote Single Sided Double Sided Single Density Double Density and Quad Density DD 96 TPI res ectively SD is the most popu lar form of Frequency Modulation M encoding while DD is the most popular form of Modified FM MFM encoding Note that in a few systems other schemes are used For example ATARI com uters do not use true DD in systems using their 510 and 1050 drives We will rep ut a type of 1 5 density called dual density enhanced density and even double density BASF is popularizing the 15 25 1D 2D 4D designations for 55 DS SD DD and QD respectively The term TOO and S13 are shorthand for Track 0 and Sector 13 See GLOSSARY tor other disk drive and diskette terms DISK SERVICE MANUAL 1 1 Disk drives are complex in thei i electronics and precise i mechanics When taken care of they can last for decades NOTE proper y service a drive one must usually remove the drive from loosen remove screws parts thu
97. es Read If they e cksum bytes the gre ree scheme t implement However it s not as reliable as EDC because errors that compensate other in magnitude will still produce the same 10 3 7 6 APPLE FRANKLIN MILLIKEN nd BURROUGHS microcomputers use checksum EDCs DORE uses an even parity scheme i i troller Reads a sector it ms using CRCs every time the con tro 2 byte numbers known as SRC sone et the end the of the Sector Header and one at ol culate header or user sector ler uses a complex algorithm to calc TI sector Verifies the CRC In Reads bytes and then Read Writes or wee CRE it ifi ares the sector byte calculations to tne or Error results usually indicating either a damaged diskette or some head misalignment ifying field its from a complex algorithm for Verifying fie controller AEDE and E US i and Verify CRCs than the one calculated during a READ H they dif fer CRC or parity type error results i i i r because parity usually refers to a bit ud o denote whether the total number of all other set bits in a grou is even odd The 16 bit CRC is the remainder when the divides the data bits by a generator polynomial V ee divides the sequence 5 Mid hen de READ CRC bytes by G x H no detectable
98. etary text and illustra tions please send us yout maruscript We wil take photos upon your direction Please let us know what your needs and ideas are We are willing to consider ANY CHANGE on a cost plus basis And quantity dis counts apply The more copies you order the better deal we can make you extra charges are negotiable and will depend upon extent and types of changes and the quantity ordered NOTE CONSUMERTRONICS CO maintains total Copyright rights to all printings and editions of all versions of all of its publications Under no circumstances will a special printing or edition confer Copyright rights to the purchaser 9999499099 Consumertronics Co 201 DR O DRAWER 537 ALAMOGORDO 88310 ISBN 0 934274 01 0 M M 4 4 4 4 4 9 9 9 9 9 9 9 9 5 9 part of this publication may be reproduced any means whatsoever without the express written permission of CONSUMERTRONICS CO O Drawer 537 Alamogordo NM 88310 COPYRIGHT INFRINGEMENT IS A SERIOUS VIOLATION OF LAW AND IT 15 THEFT PURE AND SIMPLE Becouse of the widespread practice of copyright infringement we make this special appeal to ask you to refrain from infringing our copyright if infringing our copyright was your intention and to refrain from providing this public
99. ey can also be purchased from TANDON RADIO SHACK SHUGART and other sources in the case of DDD diskettes you cannot backup diskette using an ordinary drive because some of the tracks created on it are off center and they are produced by a special disk drive If you go the professional CE route and your bad drive eats your 540 590 alignment diskette which is not uncommon you are out 5555 NOTE The software CE data diskette and procedures used in the CE alignment method are different than and incompatible to the DDD data diskette used in the DDA software only method of drive alignment According to some experts the CE method can pro duce more accurate head alignments than the DDA DDD method However the CE method alone is totally inadequate because it fails to directly test drive speed Read Sensitivity sector index ac justment clamping eccentricity azimuthal alignment and 0 sensor and end stop positioning In other words a CE aligned drive may pass the CE tests with flying colors and still not func tionl Usually for the price of an alignment 20 550 that s all you get The vallgned drive can be returned to you still totally non functional ditional repairs will cost you much more even when no parts are required WESTERN DIGITAL CORP FD 179X 02 FDC FAMILY ALL TYPE COMMANDS REAO ADDRESS NOT REAOY 9 NOT READY WRITE PROTECT WRITE FAULT 0 WRITE PROTECT WRITE FAULT
100. fea tures and options are 1 DRIVE SELECT 055 are indicated alongside provided 355 as either 051 054 DSO DS3 some drives are limited to only two r three DSi s The JS labels are usually very small and hard to i If your drive cable is unkeyed ungapped you must make the wppropriate DS JS one and only one DS must be selected The selected DS need not have any relationship to drive physical position If your drive cable is keyed gapped you must select the DSi that corresponds with the cable keying you can fact JS all 0545 without problem If your system uses only one drive you must JS MX if not MX must not be 25 2 SIDE SELECT Most modern DS drives permit JS selection of the drive as either one DS drive usually the default or as two separate SS drives Modifying a DS drive to two separate SS drives usually requires disconnecting the side select input to the side select circuitry and connecting the second DS to the side select circuitry 3 ACTIVITY LED ACTIVATION Several options are available in some drives Activity LED ON upon A Drive select B Ready pre ready C In use 0 Any combination of drive select ready pre ready and in use By far 15 most common Some 8 drives have solenoid door latches that usually activate upon activi ty LED activation In no case should the activity LED 5 to be OFF during disk access HEAD LOADING Two head loading options ar
101. fingers Evenly and firmly press down upon all socketed components Power up again and test INSPECT FOR BAD PARTS About 75 of all electronic malfunctions leave some sort or visible damage Look for burns smoke stains sweats Cracks pin holes and exploded parts Electrolytic capacitors usually leak sweat crack or form bulges at the plus end With age clock backup bat teries sometimes leak and must be replaced and the area cleaned Up IC coloration is an important indicator The center of the IC should be the same coloration as the rest of the If the center looks a lighter shade dull blistered or crystallized it probably over heated The parts to go first are usually the hardest working parts Except for power supply parts the most endangered are peripheral drivers Then the pP FDC RAM and ROM Peripheral devices usually pro gressively malfunction as heat progressively degrades their integri ty If you do get into your computer you should if possible heat sink all of these parts PARTS SWAPPING Once you ve isolated the part of the system or circuit that is ap parently causing the problem you can swap out parts just like the ros do Unless you have spare boards electronic swaps will usual be limited to cables and socketed ICs Unless you have spare mechanical parts there isn t much you can swap out in your drive if your problem is mechanical Swap out stepper motors head assemblies and TOO Sensor and E
102. ghly recommended to replace 5 300 8015 INECTOR HEAD CONNE SHUGART 5 801 SHUGART SA 301 8 SS 77 Tk 8 msec Lead screw actuated The SA 801 is identical to the SA 800 except that it is also compati ble to non IBM systems One of the first and best of the early 8 drives the SA 800 801 is still widely used MRIS CEN 9
103. gthy program in which most of the bytes are the same for example a BASIC program with a lot of nnnn DATA 222 statements nnnn Line The object is to align the head until the analog voltmeter output maximizes usually at about 3 volts Do not use a digital voltmeter response is too slow Before use verify that the 1480025 not shorted One microprobe is placed on an analog head signal pin while the other is placed on one the drive s Ground pins The signal pin is found by tracing the logic card s circuitry back from its head con nector You want the ANALOG head signal preferably the output of the analog amplifier not the DIGITAL head signal If you can t tell by the circuitry you can tell by slowly lowering the head onto the spinning diskette If the signal progressively increases you have an analog pin if it increases abruptly you have a digital pin In most modern drives the analog amplifer and digitizer are pack aged together in the same hybrid IC In that case carefully probe around the IC s pins until you find one with the analog signal This circuit can be integrated into the Drive Test Station des cribed herein 8 IBM 50 PIN STANDARD 360 RPM WRITE CURRENT SWITCH SPARE ALL 5 AND 8 ODD PINS ARE GROUND GND 5 IBM 34 PIN STANDARD 300 RPM IN USE HEAD LOAD SECTOR INDEX READY SECTOR RESERVED g
104. he diskette the diskette with a finger 2 For more regular operation you can temporarily clamp the diskette by using a small wooden plastic or rubber wedge gently inserted between the edge of the door frame and the cone lever assembly manually clamp the cone onto 1 F nqHU M MM M M U U U U U U U ither pressure should steady but be sure that you doni m too pressure particularly in DS drives i isk to damaging the front panel is by removing it to dhe PIRE en its n screws too tightly ang stripping them out lf the front panel can t be properly mounte 1 more than likely you ll get DRIVE or DEVICE NOT AVAILABL error defect ve front panel usually has to be replaced el LED drive access lamp will occasionally burn out I Ud not drive operation It is there only to inform the user when the drive is selected First verify its connection at the logic board To replace it you must strip out the old RED y clipping off and removing cable ties and disconnecting the L gt art the logic board Then back off the LED retaining collar and slip the L D out of the LED holder Press in the new LED install its retaining collar properly route and tie up its cabling and connect it at the site of the old LED connector HEAD LOADER ive s head loader does not reliably operate the problems d bet don to Electronic malfunction B Defective or dirty solenoid or
105. he fiow of data from the FDC during a READ WRITE The software was unable to fully Read Write the current byte o data before the next byte became available to be Read Written Primariy due to incorrect drive speed or bad diskette 7 READ PROTECTED SECTOR The sector DOS Read was of a Read Protected sector not necessarily in error 8 DRIVE or DEVICE NOT AVAILABLE The currentiy selec ted drive is not available for access disconnected turned OFF im properly inserted diskette defective Sector Index Optical Coupier speed far off etc 9 DISK DRIVE FAULT A hardware defect or dis connect in the controller drive interfacing and or drive 10 WRITE PROTECTED DISK ETTE The diskette either has a Write Protect tab is inserted in the wrong way or the Write Protect Detector or related circuitry is bad The 1 source on floppy drive theory and practical facts is DISK DRIVE TUTORIAL ONSUMERTRONICS Drawer 537 Alamogordo NM 38310 If you still want more information on diskette directories file storage passwords error recovery methods and disk I O operations Saqi TRS 80_DISK MYSTERIES and MAC ANGUAGE DISK amp OT MYSTERIES INC 1953 W 11th St Upland CA 91786 7 2 HER DRIVE STORAGE CAPACITIES WESTERN DIGITAL UNFORMATTED CAPACITY NOMINAL 109 375 218 750 218 750 437 500 401 016 802 032 802 032 1 604 064 DENSITY
106. he time to clean and lubricate your drives you can prevent 80 of your disk drive repair expenses without touching a single electronic instrument Consumertronics Co 2011 CRESCENT DR P O DRAWER 537 ALAMOGORDO NM 88310 DS SHUGART 5 465 1 000 000 untormatted 6 250 track IBM 16 Sectcr 55 360 4096 track 256 sector Non IBM 10 Sectoc BYTES TRANSFER RATE 250 000 data bits sec 31 250 bytes sec RECORDING DENSITY 5 922 bits inch COMPENSATION Write 0 125 us Read Automatic 764 779 7 peed The replacement multi turn 20 25 turns pot and resistor pes ar IR a ro Zo a ies Re bc ri Ne ua eS Chapter SPEED ADJUSTMENT In this chapter the term motor refers to the spindle motor also known as the drive motor or the servo motor No references are made to the stepper motor Speed pot refers to the drive speed adjustment control pot Pully refers to the spindle drive pully Belt refers to the drive belt Drive speed refers to the drive SPINDLE speed Spindle and motor speeds are the same in drives that use direct drive motors In belt driven drives the motor rotates much faster than the spindle For example when we Haii rotates at 300 RPM 5 the motor may rotate at 2 000 300 RPM 5 RPS refers to the 5 IBM standard 360 RPM 6 RPS refers to the 8 IBM standard Some newer ultra dense 5
107. head assembly left side of drive is also temporarily removed It is recommended to punch two 0 25 holes use ROPER WHITNEY sheet metal punch not a paper punch in the removed glassine window so that future lubrication and clean ing can be made through the holes without removing the window Parts that should be lubricated include 1 The drive spindle servo motor both sides 2 The drive motor spindle behind the large pully squeeze the lubricant nozzle between it and the drive wall Does not apply to drives with direct drive motors 3 The Read Write head assembly s guide bar s Prior to oiling them wet a cotton swab with alcohol and wash down the guide which serve as linear bearings sure that all dust dirt lint tobacco byproducts etc are removed Be sure that the oil is dispensed uniformly around the periphery of the guide bars in several spots Do NOT oil excessivety 4 The contact between the stepper motor shaft and the Read Write head split band 5 The spiral wheel or worm gear grease such as WHITE s lubricant 6 Behind the hub and cone accessible in most drives through the door even though drive makers claim that spindle bearings never require lubrication 7 Contact points between the head carriage assembly and the door closure assembly 8 Front panel grooves for the door posts and the door hinges particularly in TANDON SHUGART and other drives with pop out doors if plastic u
108. heat shrink tubing except the tip so you don t accidentally cause a short circuit In most drives CW increases speed CCW decreases it SYMPTOMS amp CAUSES The drive may be out of speed adjustment when DRIVE DEVICE NOT AVAILABLE errors result The drive is less severely out of speed adjustment when LOST DATA errors result during a Read Write This means that the CPU can t catch the data as fast as the controller is taking it off the diskette Lesser degree of speed out adjustment may cause or contribute to other Read Write type errors Alignment Read Sensitivity hysteresis and clamping errors are all aggravated by drive speed out of spec In most drives the motor speed is not affected by AC line tre quency or DC voltage level up to about or 3 volts However as the motor continues to operate it may slow down due to its con trol electronics heating up Instantaneous speed variations are due to non uniform wear slip ping or binding in the motor belt and spindle assembly pully hub bearings hub the belt being the most likely culprit It may be oily dirty deteriorated or stretched any of which can cause slip page H the belt is contaminated use a Q tip dipped in alcohol to run over the belt and pullies to clean it To test to see if the belt is stretched rubber belts first clean it and the pullies as above and allow to dry Then momentarily arrest the pully by finger pres sure on it and if the belt
109. icate the drive If problems still persist Unless otherwise noted most of the repairs indicated below are described in the miscellaneous repairs chapter 1 DRIVE NOT READY AND OR NO INDEX SPEED CAN BE ADJUSTED A Diskette Not Or Improperly Inserted Correct orientation B Door Not Closed Close drive door Replace broken door Verify operation of door switch if drive has one C Drive Not Selected Veriiy proper jumper configuration and connections Switch drives to test controller Drive Select func tion D Disconnected Index Sensor board usually P10 E Maladjusted Index Sensor LED and or photosensor F Defective Index Sensor photosensor G Bad Index Sensor Electronics Replace or repair logic board Poor Compliance Replace felt pressure pad adjust upper arm assembly repair replace head loader or clamp assembly replace head carriage assembly repair replace logic board D EMI Usually ntermittent Verify proper drive and system grounding Verify proper head shielding Verify proper drive cable routing stay away from 120 VAC and the CRT Verify that EMI is not coming from the computer 120 VAC line or power supply 2 DRIVE NOT READY AND OR NO INDEX SPEED CAN T BE ADJUSTED A Spindie Speed Out of Adjustment chapter B Defective Belt Verify that the drive belt is not worn frayed broken slipped loose or oily clean or replace C Disconnected Spindle Motor Verif
110. ing screw s Having adjusted the sensor you MUST realign the drive While doin turn the end stop set screw IN until the end stop is softly in contact with the head carriage assem bly at TOO Then back OUT CCW i 4 turn The end stop wili then be correctly adjusted Consumertronics Co 2011 CRESCENT DR O DRAWER 537 ALAMOGORDO NM 88310 an AUTO BASIC A A A slowly m s n ma sma w s s s u s s w w DISK SERVICE MANUAL 111 R W HEAD ALIGNMENT 5 CLOCK BITS DATA BIT CLOCK BITS UF PRESENT CELL gt 50574 26 PATTERN SHUGART DATA BITS 50574 27 CELLS SHUGART REPRESENTATION OF 54 1 1 1 SHUGART BIT 1 i i 1 i D D 1 fE 0 DATA BITS CLOCK BITS HEXADECIMAL REPRESENTATION GF DATA BITS CLOCK 8115 50574 28 FM 2 4 asec 7 ake z BIT jf o I a 4 0 5 D C D d 1 2 gt 26 jee lt 50974 30 ENCODING SHUGART Index interval 166 7 2 5ms Pulse width 1 8ms Burst delay INDEX TIMING Pre amp output Index burst delay TYPICAL SECTOR INDEX SPECIFICATIONS TEAC mm M 9 iod D D eumdem amt s ee As ei em 5
111. inspect and gently with dry fingers feel around the logic servo motor and power supply board ents CAUTION Avoid touching the larger power supply power transistors and resistors some run very hot and the 120 VAC nections If anything feels burning hot produces smoke or looks or smells scorched although the drive may not now be defective drive prob lems are sure to occur in the near future Also if a component should be warm but is stone cold instead it could either be de fective or not properly powered or grounded Correct any problem NOTE The finger test is just a first test A component can have a perfectly normal temperature and still be bad Most people s fingers aren t sensitive to small temperature changes A simple and effective thermal tester for components is described in the May 1985 issue of RADIO ELECTRONICS p 110 CONSUMERTRONICS 2011 CRESCENT OR DRAWER 537 ALAMOGORDO 88310 DISK SERVICE MANUAL IIT Vill 1 properly operated along their power components when curve will not wear out until Kingdom Come Howe do not always catastrophically fall When a near its limits sometimes becomes overworked and overheated and increasingly degraded until it works only intermittently and then fails Driver nd interface ICs are particularly vulnerable to long term thermal degradation Should you suspect electronic degradation pr
112. ion simply by switching the various TW switches so that the proper inputs and Ats are wired for the DUT it is also a great help in determining unknown ICs lot of ICs now have proprietary numbers even common ICs The Tester Emulator can also be used as a Substituter if the in situ device is totally dead by switching Verifier IC output TW switches from Pos 3 to Pos 5 By expanding upon these circuits ICs with greater number of pins than 6 can also be tested One standard size of TW switches is eight positions The two extra positions can be used for additional Clock and Pulser inputs One clock can be used as the Clock while the other as a Data Input And many digital ICs require more than one contro voltage 5 Tower NYON AUDIBLE LOGIC PROBE The audible lorie probe is a nifty device that audibly tests ICs for 1 and 0 outputs It does this by generating low tone for 0 5 and high tone for 1 5 Designed for TTL use only it is easily modified to CMOS by changing the resistor ratios defined by the 30K 12K and 8 2 ohm reference resistors Shown they produce a high tone for inputs of 3 04 volts and low tone for inputs of 0 3 volts 220K volts Vd Vdd High 7 volts Low 3 volts At 15 volts Vdd High 11 volts Low 4 volts See ULTIMATE LOGIC PROBE 57 CMOS and lows depend upon supply voltage Vdd 5 the logic probe design consider to the ulti
113. ipment chassis case Resistance should be 20 M ohms Then run a continuity check between the 120 plug s earth chassis ground prong to the chassis Resistance should be zero Then use a line checker device to check your com puter s 120 VAC wall and power strip outlets to verify that the se ed correctly many are not 1 your drive is ever subjected to line VAC on either a age or ground bus consider that the entire Logic Board is well as the Sector Index Optical Couplers and possibly the Servo Motor Board However drive mechanics should still be all right The computer and other peripherals may also be damaged or de stroyed To minimize this possibility be very careful that you do not pinch an AC line when you re install your drives and drive en Closures and use recommended fuses only 3 Do not expose drives to extremes in tempera idi Cool temperature and low humidity are ideal Athlon ture shouid 50 90 degrees Changes pressure Cause drives to breathe resulting in contamination Don t use drives as shelves for books and papers or enclose them where they can t ventilate They must freely vent heat Put at least 1 4 of space between standing drives for ventilation purposes We paste the cover sides of our free standing drives squares of 1 4 thick rubber Separation is maintained and the dri rives y other when moved 4 Don t expose drives to loud noises vibrations o i u
114. itch may be either a microswitch or an optical coupler hey are located in the drive in juxtaposition with the write protect notch es of the inserted diskette SS and DS drives have switch drives have 2 The write protect switch seldomly if ever gets out of adjustment or goes bad Microswitches by far give the most problems and their problems usually only require the adjustment of the switch tang When the write protect switch goes bad your drive may A Produce WRITE PROTECTED DISK type errors for non write protected diskettes most common B Write to a write protected diskette Bad alignment can be either in height or linear position Adjust ment simply entails either adjusting replacing the microswitch tang or loosening the switch assembly sliding it into correct posi tion and then retightening the assembly Don t over tighten as the switch can be damaged If this does not cure the problem then the switch or less likely the write protect circuitry on the logic board is bad or the switch is not properly connected If an optical coupler the write protect detector may only be dirty and is simply cleaned DOOR amp DOOR SWITCH If the drive door or door switch if it has on get a DRIVE NOT AVAILABLE error Some drives use a micro Switch as the door switch Other drives depend upon lack of furce tion of the sector index optical coupler to provide the door indication e is defective yo
115. kette The read data iine should produce a stream of data pulses 4 POWER CONNECTOR POWER ON OFF 15 47 ELECTROLYTICS C TANTALUM VOLTAGE 5 VDC REGULATORS 7 INDEX BNC WRITE ey 5 74 5123 b TRACK 00 WRITE PROTECT READ DATA INDEX LED 1 5K 3 4049 o 8 2 l uen 15 150 34 EDGE CONNECTOR 5 478 INDEX psi 5 vDC 1 14 1 step our I 47K SIEP MOTOR DIRECTION Q 20 STEP 22 WRITE DATA i i l 2 WRITE ON OFF D Rep l I WRITE GATE lt 26 TRACK 00 WRITE PROTECT 4049 b CAPACITORS ARE CERAMIC UNLESS DENOTED OTHERWISE CAPACITORS ARE IN vf UNLESS DENOTED OTHERWISE RESISTORS ARE 1 4 WATT FILM Tix Observe the head carriage assembly Switch DIRECTION to IN and activate STEP several times Observe head stepping Switch DIRECTION to OUT and repeat STEP activations The head should now step OUT Continue steppin OUT until the T00 sensor in the drive activates turning ON its LED in the Station The Drive Test Station will Read data from a Formatted diskette or to an unFormatted one Written to previously If the diskette contains valuable data be sure to write protect it to avoid accident ally writing to it Drive speed can be adjusted by using an oscillo
116. lectronic troubleshooting purposes n you Bye ircui i an use plastic str 5 hue a blow drier set for no heat and a plastic bag p p e ffending subsystem then ve the cover of the offending y ORO When the problem occurs spray the coolant on suspect A ICs connectors electrolytic PT AE Moving nechanical parts drives but not on the Read Write head ny functional or error message changes olg no ape part 2018 ed i i art or close to it Carefu 5 ss Kolder and flux and excess flux vith ad hol Do the errors re occur If so or the part is damaged deformed or discolored replace it If the errors still persist Sus pect a cracked board trace or other defective part near the part idi be a problem because it can result in a Symptoms can be similar to thermal roblems If the computer room is warm and dry particularly in Min use a room humidifier Never operate computer prx when the relative humidity is less than 10 or greater than im Static charges can result in either temporary or permanent mal function and is a major reason for circuit failures i i ircui d with ting live powered circuit board wi AC or voltage on it avoid skin and metal contact with ms sections and components and with anythin near the NOT wear rings or metal jewelry MA SP insi i a Keep all liquids a Pepe owe are Alert and can concentrate and when there
117. m may be caused by a combination of factors Once the logic board is verified as the culprit using the manu facturer s manual and a magnifying glass trace the circuit on the logic board Examine each component and trace carefully ICs don t usually fail without leaving a visual clue scorched exploded Sometimes bad land solder defect short will show up Circuit chiller can uncover a thermally related failure If the problem is stil not evident then examine power control and signal lines going to and from the suspect circuit using an oscillo scope logic probe or meter We ve designed a super logic probe with many powerful features For its plans please send 6 for ULTIMATE LOGIC PROBE CONSUMERTRONICS Drawer 537 Alamogordo NM 38310 If all signals are OK carefully remove and clean the circuit board both sides with alcohol and a toothbrush allow to dry then recon nect and test When handling the board be careful that you don t inadvertantly cause short circuits by bending parts and test pins If that fails remove the board and carefully unsolder and replace components ICs first then transistors and capacitors in the sus ect circuit one at a time working from the circuit s input stage est operation after each replacement If that fails you either missed the problem or it lies somewhere deeper in the logic board At this point a decision should be made by you as to troubleshoot ing further
118. mate versatility capability sow MANUAL III NW 5 nup 9 5 ELT 3 High 3 5 volts Low 1 9 volts At 10 volts o gV DAD Drs dae TONES DISK SERVICE DIAGNOSTICS amp TROUBLESHOOTING Pas PULSER 3 Pos 5 gt oF RELEVANT 2 SwitcHes He IC TEST Cue Consumerironics Co 2011 CRESCENT DR P DRAWER 527 ALAMOGORDO NM 88310 Lr ES a SPKR VOLUME 3 34 4 13 MC M 2 LM 339 QUAD C afi OM PARADOR 4 NOTES 1 Check select function check dip shunt and cable 2 Check for proper track B alignment and the freeness of the head assembly USE NO LUBRICANTS 3 Check track 00 alignment 4 Check head amplitude and for freeness of the head assembly 5 amp 6 Check complete alignment head amplitude raw data for filter and pin 5 for proper voltages and noise HAROWARE ERROR NOTE x1 RUN DRIVE SELECT TEST RUN AUTO TEST ON SUSPECT DRIVE HOW TO TROUBLESHOOT DISK DRIVES ren te ee ee INSERT ANOTHER HARDWARE T IN DISKETT FORMATTED YES SEEK pande EST NO CLOSED YES ERROR i DISKETTE ERROR Soda DISKETTE IN El 3 RUN NOTE 2 i RUN RESTORE TEST NO 8 HARDWARE ERROR XES ERROR SWAP i
119. misalign the Read Write Head felt pres sure pad and or diskette 3 ALWAYS ALWAYS ALWAYS back up important diskettes The three tier approach is for critical diskettes MASTER diskette Stored in a safe cool low humidity environ ment ex refrigerator safety deposit Only used to make Copy Masters B COPY MASTERS 2 diskettes Only used to make Working Stored away from Working WORKING COPIES 1 diskettes The only diskettes used in to day operations Only new high sheen bulk erased diskettes are recommended for masters DISK DRIVES 1 Never smoke drink or eat around drives or use them in a dirty or dusty environment a good policy for ALL computer equipment Keep all small metal items ex staples paper clips screws nuts metal shavings away computer systems Always cover the drives with a lint free cover after turning them OFF In fact cover ALL computer equipment when not in use Equipment exposed to normal office and household air pollutants collect lot of dust in a year s time and the lubricants dry out Dust and smoke are death on drives and diskettes because the particles get onto the Read DISK SERVICE MANUAL IH Write head s felt pressure pad and the diskette face and wear them out as if they were rubbed wi th sandpaper 2 Never remove or any connector or a dri ing
120. ms ar cheapo electrolytic capacitors that they use tion they either open circuit or intermittentl bulges holes or cracks call for immediate re acement Try suring their resistance disconnect and disc arge first using FET high input impedance multimeter while gently moving the The meter should indicate a normal gradual t charge should hold for a few minutes the large With age and vibr short circuit Carbon resistors and pots also deteriorate with age More oft than not spraying contacts on an offendin pot switch relay connector with contact cleaner GC SPRA KLEEN will cor pletely clear up its problems If you can t adjust a power supply voltage high enough to me Specs the problem could be a short or intermittent in the logi servo motor or power supply board Disconnect the drive s pow supply connector usually 2 22 Try again If good you ve got short in one of your boards If still bad temporarily disconnect electrolytic capacitors If now good replace the shorted Capacitc If still bad pull out the power su ply schematic and work backwar within the power supply failure of a 7805 5 VDC 7812 VDC 7824 24 VDC is a common cause for voltage output Its failure is usually caused by a short circu somewhere in the drive A power supply short in the logic or ser motor board could be caused by any component on that board
121. n be formatted to T42 and most 80 Tk 96 TPI drives to T84 because the sensor is set back as far as it will go A bad prac tice of some drive shops is to adjust the sensor so that the maxi mum track is now 40 or 80 prior to alignment This can make un Readable the last two or four tracks you Formatted before the drive was aligned Although you NEVER Write to 48 diskette with a 96 drive 96 TPI drives can Read 48 TPI diskettes the converse is not true if your DOS or software permits drive double stepping preferred way to align 96 TPI drives to read 48 TPI diskettes is to align TO1 of the 96 TPI drive with TOO of the 43 TPI drive Professional drive shops normally align the head s to T16 In our method we use the Directory Track which in 48 TPI drives is usually 16 T17 01 depending upon the system There are two methods of finding tracks above TOO once TOO is found 1 Formatted Diskettes Step the head in a number of times less than the target track without updating the track the FDC s track register then order the FDC to Seek the specified track by reading the diskette headers You don t need to do it this way if you have a disk utility that will tell you which tracks each of a diskette s programs occupy By designing a program data file to occupy just less than one track and Saving it to the diskette 40 or 80 times each time under a different name ex Prog07 you ca
122. n can misalign the Read Write Head s or feit pad SECTOR INDEX OPTICAL COUPLER With a cotton swab and alcohol gently clean the sector index opti cal coupler s after cleaning the head s and pad PULLY The most common cause of erratic drive spindle speed is due to the drive belt slipping on the pullies Less frequent Causes are a wocn or loose aged or defective servo motor board electronics bad diskette defective spindle motor or bearings And the most common reason why a drive won t boot after being lubricated is because oil inadvertantly got onto a pully or the belt and the belt is now slipping If you observe under a fluorescent lamp that the large pully pat tern in drive with no inserted diskette appears to be on target insert a diskette Does the drive spindle slow down considerably become erratic or stop If it does and the small motor pully is still turning the drive belt is slipping 1f the slipping is caused by an oily Surface it can be cured by dipping a Q tip into alcohol and while the drive is running empty gently wedge the Q tip where the belt comes off of either pully NOT where it goes onto the pully Dirt and oil will be quickly cleaned off Repeat as often as neces sary Allow the alcohol to dry then run the drive again CONNECTORS Some computer systems have problems with cumulative connector voltage drops The TRS 30 Modellis a classic example The key board is connected to the ex
123. n get very expen sive or finding the resistor used in place of the traditional speed ot if it has one and replacing it with a pot resistor combination his assumes that the drive speed is out of calibration due to gradual deterioration of the control electronics and or motor and not by a catastrophic failure The speed control resistor is located in the motor control circuitry and should control the gain of an operational amplifier used as a pre amp It can be tested by temporarily clipping a resistor 10 mes its value in parallel with it and observing change in drive are wired in series The values of the new resistor and pot should be about 80 and 40 respectively that of the old resistor SPEED POTENTIOMETER Some drives due to apparent superior design may never need Speed adjustments and do not have a speed pot However we find that TANDON drives in particular must be periodically adjusted for speed The criticality of drive speed errors largely depends upon the sys tem and diskette Format used Standard Formats are more tolerant than denser custom formats because dense formats soft sectored system must interpolate sector positioning to a greater uds of accuracy Systems such as DIGITAL EQUIPMENT s RAINBOW provide very little extra buffer space at the end of tracks and are very intolerant to overspeeds Some manufacturers have purposely set their drive speeds low to format more sectors per track and to frus
124. n then select whatever track you want to align to by Loading the program residing on it with the exception of the directory and boot tracks 2 Unformatted Tracks Step th head in the exact number of times equal to the target track fill the track register with the target track and then issue a Write command for the target track to force the drive to Write the track header onto the disk ette Some professionals like to be more thorough by verifying alignment of a middle track to 01 and upper end track both which can vary slightly from the alignment to 16 and each other due to small differences in stepper motor incrementations and hysteresis factors 701 alignment is more critical than any track above the Directory track There are three methods used to align drives A Cat s Eye re quires expensive and complex equipment and software but works with all drives DDA DDT software and diskettes requires an expensive program for each drive type C Trial and Error takes longer but also works with all drives Since A and expen sive and drives need to be aligned seldomly if ever C is the pre ferred way for most people and described herein The Trial and Error method can be accomplished using the simple alignment cir Cuit see figure or by the feel method described below To correct the misalignment turn computer system power OFF Remove the drive s enclosure Be sure connectors are all firmly S
125. nclosure be sure to turn power OFF Turn it back ON only as required Also verify that all connectors are secure and square before turning the power ON NEVER CONNECT OR DISCONNECT THE HEAD CON NECTOR S WITH POWER ONI SECTOR INDEX OPTICAL COUPLER justment of the sector index hole optical coupler LED photo is rarely if ever required The primary cause of Optical coupler misalignment is forcing in or out a diskette with a ragge y punched sector index window typically SS diskettes converted 25 flippy using a punch Indexing problems are sometimes a y a dirty optical coupler More rarely the LED or photosensor burns out or a malfunction occurs in the logic board circuitry itical the index alignment is depends largely upon the teller eed in your system Typically the elapsed time between the detection of the leading edge of the sector index hole and the beginning of the 500 ID Mark is 200 psec Most systems tolerate any time between 100 and 300 psec Most modern controllers toler ate much index misalignment some between 10 and 400 jec The only operation that may be adversely affected is FORMA and COPY and BACKUP where FORMAT is used Disk index alignment becomes even more critical if you are using non stan dard formats because the arrival of sectors underneath the head is computed the detection of the index pulse If you have FORMAT problems first adjust the drive speed If they sti 1 persist but all
126. nd You can gently manually move the head carriage assembly by rotating the collar or by sliding the assembly along its guide rails without any risk of misalignment split band actuated drives only Do NOT loosen a tight collar unless it has definitely slipped If you loosen the collar retighten it before making an alignment Drives that have the nasty habit of an habitually loosened split band collar can be repaired by either gluing or pinning the collar to the stepper motor shaft Before either fix be sure that the collar is in its right position Gluing epoxy cement is preferred because drilling the pinning hole through the collar and shaft is a tricky and risky operation If the expensive Read Write head stepper motor becomes defective from lack of lubrication dirt or aging it or the entire module as sembly stepper motor head carriage assembly must be replaced to repair the drive and the drive must be re aligned READ SENSITIVITY casionally a drive will develop poor Read Sensitivity although alignment appears to be perfect Symptoms are that the drive will appear to dr ft in and out of alignment with temperature and SECTOR INDEX HOLE ALIGNMENT NOTCH CENTER HOL RADIAL ALIGNMENT mites ene cvm DISK SERVICE MANUAL TIT Vil 1 time and with IN and OUT STEPs Frequent but random CRC and parity type errors and lack of reliability in Readi
127. nd Stop cautiously as an alignment is required each time Try whatever substitutions you can make Substitute various cables Switch the drives around and substitute with known good drives If not the problem is most likely located in your computer or expansion interface If you have two like com puter systems label all of their subsystems PC boards and plug in components ICs Then make substitutions This should pin point the subsystem or PC board at fault If you can narrow the problems down to one board or subsystem you usually reduce the effort by a factor of 10 the problem is in the expansion interface or computer substitute the FDC IC and any other socketed controller ICs Substitute the Substitute RAM chips Swap out the power supply ies Care fully scrub the drive controller and main PC boards both sides with alcohol and a toothbrush Allow to completely dry By doing this you might dislodge an offending solder ball splash hatr dis cover the defect eliminate an EMI problem caused by crosstalk or eliminate a short circuit SEE PHOTOGRAPHS FOR MORE DETAIL ON DRIVE ANATOMY tris a uama 5 T T sh Rs A ON m cunan nu e Ba t RENE 75 THERMAL STRESS METHODS Almost all intermittent type problems are either t ermal or stess i i t bl ither
128. never in properly cared for drives The most common type of misaligment is radial Azimuthal rotatational misalignment is rare and cannot generally be re aligned in the field Head 1 DS drives are by far most susceptible to azimuthal misalignment Its primary cause is the use of a dry cleaning diskette The entire Read Write head assem bly including stepper motor may have to be replaced Factory azimuth alignment is measured on both sides of T16 using herring bone patterns written on a special alignment diskette by a special drive Described herein is the re alignment of radial misalignments In DS drives Head 0 is aligned first If this doesn t also align Head 1 then Head 1 must be separately aligned One of the most common misalignment problems in TANDON and r split band actuated drives is caused by the collar or clamp 1 stepper motor shaft TANDON Inside glassine window becom ing loose This collar articulates with the head carriage assembly through the split band It can be tightened using a small phillips screwdriver or allen wrench We do NOT recommend testing it for tightness UNLESS you have misalignment celated problems and prior to aligning the head In TANDON drives the collar screw should point to the front inverted stepper motor screw when the head is on T16 Since the collar moves in i track increments you cannot accidentally position it between tracks You can lubricate the motor shaft and split ba
129. ng a diskette Formatted by it or another drive results More anything else what separates poor Read Sensitivity from misalignment s the inability of the drive to Read the diskettes it just Wrote to The greatest causes of poor Read Sensitivity in aligned drives are worn head poor compliance worn felt pressure pad or bad head loader hysteresis and eccentricity clamping They are caused by dirty worn or damaged head felt pad guide rails spindle bearings clamp assembly head loader and diskettes And by weak READ WRITE amplifiers and internal EMI Although Cleaning alignment and felt pad replacement usually improve Reading Sensitivity it still can be severe enough to cause great problems and ruin disk ettes Poor Read Sensitivity due to a defective or worn out head or to bad electronics CANNOT be repaired without replacing the head Bad electronics on the logic board can frequently be repaired HYSTERESIS Hysteresis is defined as the inability to retrace exactly on the reverse swing a particular locus of points ex track and sector set on the forward swing In drives the alignment hysteresis is deter mined by first approaching a track from its inner spindle side end then approaching it again but from its outer TOO end The differ ence between where the head settles in the two approaches is ideal ly zero is a measure of alignment hysteresis and is directly related to the mechanical slop between the stepper mot
130. ng to the problems the problems constant intermittent progressively TS and use or thermally relatsd occurs before afte warm up and more severely on hot cold days 2 What are the error messages and other error symptoms 3 Did you recently change your DOS or software 2 Did you recently change the location of your system or parts Did you recently repair modify add remove or re arrange the system s hardware yd relate the problems particularly to any user Partic ular sequence of events or external situations Time of day Season MN ii Was the first occurrence of the problems preceded by a line eer glitch Static discharge Spillage Shock or vibration inpoi he problems to a particular unit subsystem 8 Can you pinpoint the p T board due to noise smell discoloration diskette wear 9 How many operations are affected by the problems problems limited to drive function alone Based upon your answer to these questions consider the following TROUBLESHOOTING ADDING AND CHANGING EQUIPMENT most common problerns is adding or changing a peripher EVER your system finding that it the system or both longer work This phenomenon most frequently occurs when adding or changing drives The most likely causes are A Poor or wrong connection B Wrong drive options C Wrong system configura tion D Drive access time is too sl
131. nother 1 Systems using NEC controller ex DIGITAL EQUIPMENT CORP cannot use DDA software for drive speed or sector index adjustments simply because NEC controllers do not provide this in formation Where possible the NEC controller should be substitu ted by an equivalent WESTERN DIGITAL controller 2 Most modern drives do not have a means of adjusting drive speed Eventual component aging can throw these drives off speed wise 3 Some systems have ROM routines which require certain iden tifying bytes on the Ist track They cannot Read DDD diskettes and thus treat them as foreign diskettes and refuse to use them In some cases these problems can be resolved by logging in the drive with a normally formatted diskette IF the drive is in good enough condition to properly log on and then switching to the DDD disk ette Most DDA software requires a specific hardware configura tion and uses the DOS only minimally Any deviations can limit or fc up its use Universal systems such as CP M usually free the s of at least the computer dependence However systems thar are labeled as compatible ex IBM compatibles and clones may not be DDA software compatible Also since drives come in many different variations size density sides tracks and most DDA software will only fully test one configuration one DDA package may not support all of your drives Also so called com patible systems may have drives in which
132. nt if not the most im ennt reason for NOT buying DDA software NOTE We installed our own D a rings in our DDD diskettes without any noticeable changes 2 What if one of the diskettes are d estroyed gets say 3 years from now The company who Mold it you ae 1 be in business or support your model In the final analysis the Dia ad RIO Ren special delicate and or ex CES tO eias 2 pensive ds o any job and just stick to the basics 3 J amp M first sent us software for the 1 vare wrong model i ri mistake Still was nonc ept 1984 thei i apparent sul bug their software has bug and e are also critica of J M s supplied manual t t t how to run its various and less posi they mean However it does not describe how one actuall makes Read Write head or sector index alignment spee adjust in spite of the fact that at the end of the alignment chapter RAAN last chapter for non existing discussion fact we can t find any mention of eith the TOO sensor or TOO end stopl Nor can we find tion ofa j a make or model Drive speed adjustment discussion software comes with no illustrations or photos relatin to drive anatomy Unless you are already an expert at ali ning and ad justing drives or have on hand a copy of DISK S
133. nto place as they are held into place by pres sure only Be sure that the new ones don t extend out enough t sna diskettes by their sector index windows they should be flus with their fixtures Replacement of these components require the clipping off and removal of cable ties and the disconnection from the logic board Be sure that you install the new LED in the old LED fixture and not in the old sensor fixture and that you proper ly route and secure the cabling tely we know of no method of aligning the sector index PU Apicius er without using an oscilloscope delayed sweep trig ered by the index pulse electronic counter or DDA so S these methods the first data pulse start of index should occur 200 us after detection of the index pulse 100 300 us is the acceptable range If substantial jitter is present in the index pulse the LED or photosensor is loose or probably dirty marginal index electronics part the logic is marginal i ired is much more The photosensor alignment almost never required critical than the LED alignment because the index signal is genera ted at the sensor Verify that the LED fixture screw is just a little tighter than snug If it was loose retighten it and then retest coer ee u ua dl enn een Mus nai a GN DISK SERVICE MANUAL III
134. nue looking for TOO and will bump repeatedly against the end stop When you boot your computer your drives should step back to TOO If you hear a relatively loud thunk or series of thunks because your drive repeatedly attempts to activate the sensor the end stop is set too far forward or IN to activate the sensor With the right size screwdriver or Jen wrench back OUT CCW the end stop screw about a half turn Try again Be particularly careful when you adjust the sen sor You MUST first loosen the sensor mounting screw s to slightly loose If you fail to do this you Can damage the adjustment screw or E rings in some drives TANDON etc In some drives you must swing away the logic board and shield to access this screw s In other drives the mounting screw s can be accessed from the pully side of the drive After you finish and veri fy your adjustment tighten these mounting screw s just beyond snug Don t overtighten as you can damage the sensor If you can t get the sensor to switch at all it its connections or its logic board electronics less common is defective and should be replaced or repaired Disconnect the sensor from the logic board Run a continuity resistance check of the sensor from its logic board connector The non switched resistance between contacts of a microswitch sensor should be greater than 1 Meg ohm When switched contacts should short out and resistance between them should drop cl
135. o add a 3rd or 4th propana and Pos 8 of SWI located near Drive A must be OFF Pos 7 must be ON for a 3rd drive and OFF for a 4th a different drive model you must also is drive table Track to Track Access Time number of allowable drives number of at tempts before an error is called 5 8 hard drive SS DS SD DD 35 40 80 77 100 Track type of controller used Kasa AS REQUIRED Be sure that your drives and DOS drive contigurations agree with each other With older drives you may not able change some system times to high enough levels to produce reli able results DISKETTE amp SOFTWARE SUBSTITUTION ious known good formatted diskettes in your drives to elimi hate che possibility that the problem is due to bad diskettes or clamping Don t use master diskettes only expendable copies bad drive ruin them EVEN IF WRITE ROTECTEDI Bull erase spare diskettes and try to format inem Then Read their directories using several drives What happens If you are changin change in the DO Data Transfer Rates Try various DOSs and user software combinations on your system and run similar operations with them Do the errors go away decrease or increase Any significant changes here points to either software bugs or wrong DOS drive configurations DISK SERVICE MANUAL III y DIAGNOSTICS amp TROUBLESHOOTING SPEED ADJUSTMENT amp LUBRICATION If the problem is in a drive adjust it
136. o perform the same tests lf the disk drive is not removed from its enclosure by its owner it is usually removed at the service shop and the drive is connected to the shop s Exerciser The alignment diskette is inserted into the drive While running the drive continuously the buffered outputs of the drive s Read circuit TP1 TP2 on TANDON TM 100s are con nected differentially to the scope The scope sync is con nected to the buffered output of the sector index hole detector TP 7 TANDONs Although it will minimize jitter it is not neces sary to connect the scope s external sync to the sector index test point The scope s vertical amplifier 15 set for AC coupling and 50 mv cm the horizontal sweep is set to 50 ms cm The Read Write head is carefully moved until a precise double lobed or pattern is achieved See figure To verify alignment SEEKs are made in this order T16 TOO T16 T32 or other track gt 130 T16 ideally both CE lobes should be symmetrical and eaually high In practice lobes within 70 80 of each other in magnitude are tar geted in most shops 90 in a few Using this CE method the maximum allowable radial misalignment error is 1 10 mils 48 TPI drives equivalent to a lobe ratio of 80 100 80 With most drives with a little more work you can achieve 95 100 symmetry using the CE alignment method Drives aligned to only 70 80 sym metry almost always require a future alignment much
137. oblems use a circuit chiller aerosol to see if that temporarily improves performance Also be sure that the circuit board is kept clean and receives proper ventilation and cooling The only surefire approach to diagnose any complex electronic cir cuit is to monitor all major signals with an oscilloscope or better yet a logic analyzer However our method is simple and will catch most problems early If your drive has servo motor board most electronically caused spindle motor problems be isolated there If not this function as well as the drive electronics for all other drive functions are controlled by the logic board Here is where the greatest dif ferences in drive designs exist Drive boards come in numerous configurations and circuit designs board repair should be at tempted without heavily relying upon the maker s service main tenance OEM manual Before considering replacing a PC board clean and lubricate the drive adjust drive speed verify power supply voltages and verify all connections Servo motor boards are priced at about 50 each Logic boards ar usually over 51501 New 55 00 drives are now under 5100 DS OD drives have dropped below 130 Should you scrap your drive please donate it to us for spare parts Most board electronic failures due to easily obtained and replaced component such as a failed TTL However drive boards also contain critical specialized proprietary ICs not
138. or mechan ism and the head carriage assembly This slop is primarily due to puide rail wear and is aggravated by guide rail contamination and ack of lubrication Another cause is worn or dry stepper motor bearings A thin film of oil on clean guide rail s and stepper motor bearings helps make up the difference in looseness and can by itself cure a hysteresis problem If the slop is bad you should consider scrap ping ane drive as the replacement parts may exceed the cost of a new drive ADJUSTMENT FELT lt p PRESSURE PAD TEAC CORP UPPER ARM ASSEMBLY CARRIAGE ASSEMBLY lt gt GUIDE RAIL lt READ WRITE RAIL REPLACEMENT OF FELT PRESSURE PAD TEAC CORP P Ca ql Acetate tk des 5 1 i 3 1 1 H 2 3 1 tme dei CLAMPING amp ECCENTRICITY Track to track distance for 48 drives is 1 58 20 83 mils 24 ae Wire thickness For 96 TPI drives it s 10 42 mils 30 AWG wire Head alignment is referenced to the spindle center Fac tory limit is 1 6 mils 8 TPD The maximum allowable alignment error between the head gap centerline and track centerline for any is 3 2 mils Drives with excellent Read Sensitivity and very small eccentricity can tolerate as much as 5 mil
139. or perfor mance or reliability decreases even radually Performance changes can be subtle the number of Read Write attempts in creases sometimes beyond what the DOS is programmed to toler ate resulting in ever increasing error messages it pays to learn repairs yourself Don t be alarmed if you get an error once in awhile Under IDEAL Conditions a good drive s inherent error rates are about A SEEKs attempt million Soft READ Errors 1 bit billion C Hard READ Errors 1 bit trillion Power supply glitches and externally generated EMI can increase drive error rates by a factor of a 1 000 very common When you con pts made and bits Written and Read when operating a drive under practical usages an error mes sage once in awhile is expected But be concerned if error rates significantly increase or develop a pattern Experience drive users often learn to detect small noise level Drives and diskettes of different types and makes Sound somewhat differently Lead screw actuated drives are quiet split band actuated drives are noisy Head loaders also very noisy There doesn t seem to be a relationship between how a disk ette sounds and its reliability But one can easily pick up on functions or impending malfunctions just by sound changes When listening to drives operate ignore the normal swishing diskette sound and normal drive Step and head load sounds But chattering during he
140. or replacing the board or drive Consumertronics Co 2011 CRESCENT DR P O DRAWER 537 ALAMOGORDO 88310 SOME EMI CONTROL MEASURES IN VDT S LOUVERED SLITS WITH UNDERSCREEN FLEXIBLE SPONGY GASKET METALIZED CAT CABINET HOOD C M CHOKE D M POWER LINE FILTER amp SWITCHING REGULATOR POWER SUPPLY FLEXIBLE SPONGY GASKET GASKETED GROOVE KNITTED WIRE MESH OR 3 mm INDIUM AR SCREEN COVER SHIELDEO INTERCONNECT HARNESS METALIZED VAPOR BARRIER KEYBOARD GASKETED JOINT FOR HOUSING MATING ES PERPE se zoe te comp es Ies aque le a 1 5 srt in mai DISK SERVICE MANUAL 111 ELECTRONICS amp REPAIRS VIII 5 c DRIVE SELECT 10 microsecond minimum u P r Y DIRECTION SELECT 18 1 microsecond minimum OA CONTROLLEA FOAMATTER N x 20 1 microsecond minimum 3 milliseconds minimum DRIVE SELECT DIRECTION SELECT STEP SHUGART ASSOC SELEOTED 10 a 500 nanoseconds minimum WRITE GATE 24 WRITE DATA 22 8 microseconds maximum 8 17957 830 17937 TRUE BUS SIDE SELECT 32 He 100 us MIN 1 ms MIN be PIN CONNECTIONS z ORIVE SELECT SIDE SELECT WRITE GATE AND WRITE DATA SHUGART ASSOC TESTDEDGEEEDIi SS C wasa wama
141. ose to zero ohms Optical sensors consists of an opti coupler pair LED and photosensor LEDs are diodes and will conduct in one direction Un fortunately their forward voltage is high enough that some meters will test them open circuit ed proper polarity resistance check of the photosensor should yield a dark resistance near 5 Meg ohms but not open circuit Unless you go through the trouble of building a special fo test circuit a swap test with a nown good sensor is the easiest way deter mine if the sensor is bad If the sensor passes the resistance check the prenem is very likely in the sensor s circuitry in the logic board To adjust the sensor and end stop you may use a disk utility which will Step to the outer tracks or the Drive Test Station see that chapter Else Format a diskette using a good aligned drive Save a small BASIC program filespec A on it A should be written to TOO it again filespec B should be written to TOL Many DOSs have a DIR Allocation mode that dis plays disk file locations Or use a disk m to verify that and B occupy 00 and 01 respectively Position the Read Write head to TOI by continual ly Loading in B AUTO BASIC B B B Loos en the sensor mounting screw s Slowly rotate its adjustment screw IN CW until a TO access causes it to click Then rotate the adjustment screw IN one half turn more Tighten the sensor mount
142. ow for your system oblem with instaling drives in the IBM PC XT AT ibles is that the computer does NOT issue a Motor On Command to a drive This results in a Drive Not Available error in all drives in which the Motor On line is not internally jumpered to the DS line This jumpering 15 required so that the DS command also causes Motor On his Jumpering comes as a drive option in most modern drives In systems that require this the drive spindle motor must be stable so that the drive can reliably Read and Write to diskettes This all but limits and compat ible systems to 5 drives with direct drive brushless DC motors common t common spindle motors used with 5 drives are DC M brushes P As the drive ages the brushes wear out and spark more causing erratic start up speeds and noise that interferes with the drive s clock recovery circuit T e e tisa lot of Read errors Don t use drives with DC motors with brushes i i hours brush while DC motors with brushes last 2 000 3 000 motors expect to last over 10 000 hours and they use less than half the power Many 8 drives use capacitor start motors which run hot are electrically noisy and don t last very long Ke are adding a drive to your system don t forget to move t TRAC usuall 55 the drive the end of the cable In some 5 5 tems you need to change internal dip switches and or jumpers to gt connect the addition In the IBM PC t
143. own use this circuit The MC3437 3 RS 422 line driver is 3 state device 1 ALL PESISTORS ww z 3 lt STEP READY fw c that ee the 7438 or 7406 1 lector TTL buffer used in most comput ers for the Write Gate and Select inter face signals The MC3487 is forced to amp high output impedance state when its Pin 4 reaches logical zero It has TTL compatible inputs that will sink 4 ma at 0 5 Volts max It s ith the interface requirements of disk drives The MC3487 insures high out put state during transistion periods com puter noise is not allowed to ripple thru 5 Io the disk drive s The output 7438 7406 is usually found in the computer s circuitrv RI and R2 are part of the drives Term Res Network and depending upon manufacturer vary from 150 1 000 ohms each 2 SPECIFICATIONS CAPTURE RANGE t20 lt LOCK UP TIME 25 ALL ONE S PATTERN MFM 3 FOR 5 1 4 B 6821 Bul 880 n 8 SS DS SYSTEM WESTERN DIGITAL 179X DATA SEPARATOR DRIVE FRAME WESTERN DIGITAL CORP APPLE DRIVE Chapter Vil R W HEAD ALIGNMENT In this chapter sensor means the TOO sensor or Home Switch a microswitch or optical coupler and end stop refers to the TOO end stop or Carriage Limiter Drive alignments need only to be done Occasionally at most usual ly
144. pansion interface through a ribbon cable jumper Unless cleaned regularly the PC board connector Format 327 80 2048 track 128 Formot 409 500 2 560 track 256 sector TRANSFER RATE 125 000 dota bits sec 15 625 bytes sec RECORDING OENSITY 2 761 bits inch FLUX REVERSALS 5 922 inch COMPENSATION Write None Read Automatic 44 179 FM VS MFM ENCODING 1 207 SD 80 Track DS SHUGART SA 445 2 untormatte l25 trock 1BM 16 Sector 1 Non IBM 10 5 Format 1 Formot 819 200 5120 tcack 512 sector 1 t FLUX REVERSALS 5 922 inch 1 DISK SERVICE MANUAL ITI MAINTENANCE Y 2 contacts tarnish with increasing voltage drops resulting at each connection Eventually the 1 voltages arriving at the expansion interface are not high enough to be consistently interpreted as 5 and data garbage erratic behavior and lock up result Some drives particularly external ones can suffer from cumulative connector voltage drops Four connectors between drives and their systems are not uncommon The best ways to clean connector contacts is either with a pink pencil eraser don t use a white ink eraser or with CRAMOLIN the tarnish is erased care must be taken to remove all eraser debris before re installation DISKETTES When you find that a particular diskette is giving you a lot of prob lems it could be due to several factors The
145. paper clips use a felt tip pen or get them oily or wet or expose them to temperature extremes sunlight microwaves x rays or infrared Do not use dirty bent creased or worn diskettes Do not touch the diskette s recording surface with fingers Hold diskettes at their rear Do not leave diskettes uncovered Do not store diskettes horizontally or lay them on rough uneven or dirty surfaces or lay anything on top of them Do not use a writing eraser on diskettes the debris produced is abrasive 2 Do not assume that an diskette is a bad diskette 14 the diskette is merely dirty it can be salvaged Some drive man ufacturers do not recommend the use of any solvent whatsoever to clean diskettes We have found that rubbing alcohol on cotton or a soft Q tip does an excellent job with no known damage to diskettes do not run while wet Rotate the diskette element inside its jac while observing its surface in the Read Write Window The Con nination is usually visible Carefully rub it off or flick it off using the alcohol soaked Q tip Even diskettes subjected to the worse contamination exposure can be saved Read DISK DRIVE TUTORIAL in Recommendations Chapter 3 For shipping diskettes label the container Do not Fold Bend or Spindle Do not X Ray Contains Magnetic Material 4 TO AVOID MAGNETIC OR ELECTROSTATIC DAMAGE avoid magnetic damage do not place diskettes near magnets CRTs tele
146. pare drive power supply with optional LEDs added as shown to provide indication The 5 VDC also supplies the Drive Test Sta tion The outputs from the Drive Test Station are mostly switch closures Motor On and drive select are activated by grounding Head direc tion is OUT when grounded and IN when 5 VDC Switch deboun cing was not found to be necessary The write gate is enabled turned ON by grounding the write enable and turned OFF by opening it for read enable The STEP function is a series of negative pulses produced by the 741 5123 2 retriggerable multivibrator when the 9 pushbutton switch is pushed 791 5123 1 is wired to provide a series of free running pulses to be written to the diskette A Formatted diskette is not required This data is written to the diskette but it is only used to provide a steady signal for tracing through the drive s WRITE circuitry to verify that input data is reaching the head To operate simply disconnect the drive from your computer system and hook it up to the Drive Test Station via appropriate cables and Connector Turn the Station ON Switch the drive select switch appropriate for that drive The drive s front panel LED should come ON Once selected switch motor On to activate the spindle motor Load in a diskette and observe the sector index LED It should Start flickering The write protect LED should properly indicate the presence aDsence of a write protect tab on the dis
147. phones VAC power lines motors transformers relays buzzers bells speakers solenoids or switching power supplies or on top of the keyboard Properly ground drives and work in a static ree environment 5 Before formatting diskettes vigorously erase them one side at a time with a magnetic bulk eraser This refreshes and livens up their magnetic particles Diskettes have discrete shelf lives about five years For long term storage cool dry and clean area is much preferred Aged diskettes shed their oxide coating 6 Even in systems specified otherwise do not leave diskettes in side drives unless they are being accessed except head loaded drives that load the head during Motor On and do not turn the sys tem ON or OFF with diskettes inside Head and diskette wear and diskette heat and contamination are the same for all diskettes in a system s drives whether or not being accessed Zarefully and correctly insert and remove diskettes from drives L aot remove or insert diskettes in rotating drives with head load ers Drives with head loaders make a clacking sound when either selected front panel LED is ON or upon Motor On spindle motor is turned ON The activated head loader solenoid causes the felt pad SS or Head 1 DS to press onto the diskette surface Open ing the drive door will not disengage this contact in some head loaded drives Moving a diskette in selected head loaded drive can severely damage for
148. puter No special modification is required other than the installation of a Percom or LNW doubler board use no other doubler for DD You will also have to buy or build special cables to adapt 8 microflop y and non standard bus drives The LNW board will allow testing of 8 drives also We chose the Model I because its drives are ex ternal and thus easier to work on it supports all known standard bus 5 3 and microfloppy SS DS SD DD 35 80 80 Track drives and some hard drives and a tremendous amount of drive utility soft ware is available for it HEAD LOAD SPARE MOTOR ON GND 050 051 5 DIRECTION STEP WRITE DATA 3 5 SONY 26 STANDARD 600 RE WRITE DATA m 8 55 m RESERVED WRITE GATE SECTOR INDEX SENSOR T00 SENSOR PROTECT VRITE PROTECT READ DATA 5 IBM 34PIN STANDARD 300 RPM INCLUDES MOST MICROFLOPPIES QW 09980 ALL 5 ODD PINS ARE GROUND GND ALL 3 5 ODD PINS ARE GROUND EXCEPT PIN 115 MOTOR ON IN NEWER MODELS SONY MICROFLOPPY TO 5 STANDARD BUS titer Atem nmn f DISK SERVICE MANUAL III DRIVE TEST STATION ANALOG YOLTMETER 1N 002 MICROPROBES ELECTRICALLY CALIBRATE ALIGNMENT With this simple cir Cult you can electrically calibrate your R W Head alignment by measuring the signal magnitude picked up by the head You do this by continuously attempting to load a len
149. r cleaning we use long cotton swabs SPRA KLEEN GC and 91 alcohol Suitable spray cleaner and swabs are available in most electronic retail outlets or use a Disk Drive Read Write Head Cleaner solution more expensive CAUTION Some chemical cleaners are harmful to plastics Do NOT use these types For electronic repairs SN60 rosin solder 22 SWG and non corrosive soldering paste GC are recommended Circuit chiller spray is a very important diagnostic tool for pin pointing heat related electronic and mechanical malfunctions the most common type All chillers we tested were satisfactory Soit tacky layout wax used in layouts artwork and publishing is an ideal shop aid You can use it to temporarily hold or pick up a Screw or other small part at the end of a screwdriver or tinger You can also roll the end of a long stem O tip into it i picking up hard to get debris LUBRICATION The object of lubrication is to dispense the oil only where itis needed and not to the extent where it drips or sags Before ap lubricant inspect all the mechanical parts the Read Write ead s and felt pressure pad fcr dirt and debris A good method to carefully remove dirt and debris is to use small pieces of elec trical tape or tacky wax see above to pick them up is generally only necessary to remove the drive s enclosure to clean and lubricate a drive In TANDON drives the glassine window in front of the
150. r cord must be disconnected wall Polarity MUST be rigidly observedtt When removing and replacing drive and system enclosures be Careful not to snag wires or short pins or test points to anything Particularly observe that the power lines going to and from the 120 VAC and power supply do not get pinched or rubbed by the sure or by a board or any part Fuses don t protect you from this kind of disaster Some drives and systems have sloppy power wir ing so be careful good practice after buttoning a system back up is to run a con tinuity check between the disconnected 120 VAC plug s hot and neutral prongs to the equipment chassis case Resistance should be 20 M ohms Then run a continuity check between the 120 VAC plug s earth chassis ground prong to the chassis Resistance should be zero Then use a line checker device to check your com puter s 120 VAC wall and power strip outlets to verify that they are wired correctly many are not If your drive is ever subjected to line VAC on either a DC volt age or ground bus consider that the entire Logic Board is ruined as well as the Sector Index Optical Couplers and possibly the Servo Motor Board However drive mechanics should still be all right The computer and other peripherals may also be damaged or de stroyed To minimize this possibility be very careful that you do not pinch an line when you re inst all your drives and drive en Closures and use
151. resorted to if all else fails The various timing relationships of each part to each other are critical in the proper operation of a computer Fortunately since your system was once a fully func tional system timing problems will usually occur only due to the aging of an already marginal IC which along with heat cause in creases in the propagation delay Usually high temperature ag gravates the problem and the marginal or failing IC can be dis Covered using a thermal method To solve timing problems a thorough understanding of system and individual part operations is a must So are excellent eyesight bench and tools and schematics with voltages waveforms and timing info Also you will require a logic probe an oscilloscope dual channel 50 MHz 10 1 probes minimum and possibly a logic signature analyzer Unless you have all of these it s time to call in the pros MORE SOURCES For additional information and photos on drive maintenance and repair see 80 MICRO Sept 1985 p 83 For APPLE drives see A March and April 1985 0000000000000000000000000000000000 TROUBLESHOOTING GUIDE Below is listed drive malfunction symptoms followed by possible Causes and recommended remedies First test with severa disk ettes to verify that the problem isn t caused by media or by inad vertent bad clamping Then clean the Logic Board and system con nectors and verily or replace the drive cable Also properly clean and lubr
152. rive speed modification you have turbo version the drive speed software was not designed for your model or there is defect in your computer s clock or a software bug Drive speed can also be easily adjusted without any special soft ware First remove drive enclosure then operate the drive with motor running until warm most drives the pully is connected by a belt to the motor The pully is about 2 5 across It should have two concentric zebra like patterns on it The outer pattern is for 60 Hz AC power systems the inner pattern is for 50 Hz for eign If your drive is an older one the pattern may have fallen off or been removed in a shop 8 drives do not have this pattern Neither do modern beltless drives SHUGART 465 and TEAC 55 Neither does the NEWTRONICS drives used with COMMODOREs ALPS drives have the zebra pattern your 5 drive uses pullies and does not have this pattern you have our permission to photocopy one of our drive photos with a zebra patterned pully cut out the zebra pate tern and then glue or tape it onto your drive s pully Regardless of your 5 drive s pully size the pattern will be correct 24 bars 60 Hz 20 bars 50 Hz For 8 drives and 5 drives that spin at 360 RPM the 5 50 Hz pattern 20 bars is correct for 60 Hz m power Turn OFF all incandescent lighting Turn ON a neon lamp over the pully To adjust the s red
153. rives to DS simply by replacing the SS head carriage assembly with the appro priate DS one ex SA 410 to 5 460 Although SS to DS mod is possible note that DS drives frequently use a different logic board and stepper motors and use a mechanical head separator not found in their SS versions Logic boards that permit the connection of two head connectors frequently found on SS drives can also be used on DS versions Also if the drive develops Read Sensitivity problems due to bad electronics you can the head connector to Head 1 electron ics in SS drives or swap both head connectors with each other in DS drives Also be sure to swap their 21 connector DS pins Head electronic swaps are also a method for testing suspect drive elec tronics OTHER DRIVE MODIFICATIONS Other drive electronic mods can be made Some folks install toggle switching of motor On switched ON by grounding the motor On line and head loader also activated by grounding the head loader line MECHANICAL MODIFICATIONS The two most frequently encountered major mechanical mods are described below I ve successfully attempted both of these mods and will vouch that they are both very difficult and risky to m They should NOT be attempted because the required disassemt j extensive the drive frame is a bear to work with and the resultant rough handling and debris are intolerable 1 Conversion of SS drives to flippy by installing an additional
154. rm assembly to the head carriage assembly By loosening these screws nuts the upper arm assembly can be moved around a little to recenter it on the head If pad wear is highly uneven use a small fine file to even it up Retest for reliability then GENTLY retighten the screws nuts Make this adjustment first if compli ance does not improve then do 2 2 EVEN PAD WEAR In most drives there is a head pressure adjustment screw It is found on top of the upper arm assembly on top of a structure called a spring retainer Just above a 1 2 or so skinny spring between it and the rest of the upper arm In many drives this tiny screw is boogered up with loctite or paint and isa If possible tighten CW this screw about teal chore to work on DISK SERVICE MANUAL III MISCELLANEOUS REPAIRS X 2 one turn to increase the spring force and thus felt pad pressure Too much felt pad results excessive head and diskette wear If it was adjusted earlier and you replaced the pad you might want to back off CCW the adjustment screw 1 or 2 turns LOGIC SERVO MOTOR BOARD Replacement of the speed control electronics entails replacing either the servo motor board if the drive has one or the logic board The electronics for all other drive functions including stepper motor function are located on the logic board For the logic board 2 3 or 4 screws must be removed and the board slid back until its notches line up with the tabs
155. s voiding ocu may apply While every attempt has correct and complete information in thi comprehensive manual we do not assume responsibilities for Ta assume no whatsoever for loss a indirectly alleged to b the information fo i lt deep fh und herein DISK SERVICE MANUAL is sold as The phrase remove drive enclosure simpl of whatever the drive is inside of to do the defined task In tee standing drives the enclosure is simply the drive s cover Most drives are inside computers or expansion interfaces in which Pie remove enough of the computer or expansion interface s enclosure Cables and subsystems to physically access the drive Most dri worked situ SAVVY ADVICE Mr Mike Wolinsky President of FLOPPY D ISK SE in the Aug 15 1983 issue of COMPUTER SHOPPER One due n asked by my customers is what mai Y perform themselves answer is simple Red Mod designed with MTBF This is an estimated design lif efore repairs are needed dics In some cases Mr Wolinsky is ri i linsky is right Some people simply were not 222 is reasonably bright alert A and careful and is not clums does not need to be trained 3 dri r eed at a drive shop or be c i maintain computer equipment Whether es his ua wor or not to wait until the MTBF arrives is plain idiocy The savvy person performs or
156. s of misalignment Halve these tolerances for 96 drives i ecome impossible to align if the spindle hub shaft yu cone DESI worn or bent The result is that the diskette rotates in an eccentric manner so that the head w may be perfectly aligned at one sector traverses to another trac as the diskette turns 180 degrees This happens because the center of the axis of the diskette is not precisely aligned with that of the ideal spindle The same symptoms result from the more common problem of a distorted diskette center hole Eccentricity also results from improper diskette clamping Carefully reclamp a disk ette with the drive motor running but drive not selected to elimi nate a considerable amount of eccentricity OTHER PROBLEMS isali i i ladjustment or the misalignment is caused by a defective maladjus installed drive stepper motor drive guide rali head carriage assembly or end stop or sensor you we not ae le to correct the problem completely by aligning the Read Write head In these cases unless the cause is obvious and correctable by you ex broken door 00 probiem you should send the drive to a pro essional shop UU I7 MISALIGNMENT imary causes of drive Read Write head misalignments T Shock and vibration most frequently cause by either drop ping the drive or dropping something on the drive particularly drive is operating Mic popu dirty Side rails The head carri
157. s speed Clean and lubricate it About 90 of drive problems are due to speed out of adjustment lack of lubrication or contamination Label and switch drive logic and servo motor boards and power supplies CONNECTOR amp CABLE DIAGNOSES The most common computer problems are cable connector problems which most frequently occur after moving re arran ing or working on your system And after physical accidents Examine all ex ternal cables and connectors With your system OFF remove all external cables and examine connector contacts both in the Cables and on the hardware Are there any bent broken or corroded tacts Are the cables all suspect damaged cables and connectors Carefully clean either using a contact cleaner solution CRAMOLIN or pink pencil eraser remove debris all connector contacts that appear to be dirty or oxidized tar nished After re installing the cable connectors squarely and firm ly but don t force repeatedly turn the system ON and OFF and watch for errors Did they go away Are they better worse or about the same Try lightly jiggling the various external cable and connectors Changes in errors indicate a cable connect problem A related problem is a socketed part that becomes loosened due to shock and vibration These parts are under spring tension from the socket contacts and the pins can slip out simi arly to a water melon seed between your
158. se vegetable fish or baby oil 9 Contact points tor any other moving mechanical parts CAUTION Do not lubricate the drive Read Write head s felt pressure pad pully surfaces pully belt optical coupler s any wiring and electronics including connectors and non moving parts Gently wipe away or swab up any excess lubricant Use quality small motor es i 7 2 baiiio 4222 c I far as we know all drive stepper motors have sealed ball bear 8 However spindle motors have brass bushings at both ends id must be lubricated at least once a year or once per 200 hours of eration The rear of the spindle motor usually fits into a col ed plastic em Removal of the Logic Board may be required to ide this cup off to apply the lubricant LEANING READ WRITE HEAD lean Read Write head s and felt pressure pad are crucial for both Hn and diskette life The head s and pad are cleaned after ibrication easiest and fastest yet effcctive way to clean heads and ads is by using a wet type diskette like head cleaner CAUTION Jever use a dry type diskette cleaner We recommend the ERBATIM Read Write head cleaner but only for occasional use Mechanical head cleaners a safe and effective way to clean the heads on tape recorders but NOT on drives The difference being tha
159. sed near airports railroads major highways nau ites where noise and vibration levels are high experience very high fail ure rates High noise produces micro vibrations that rapidly deteri orate drives even when they are not being used Our drives rest on 1 2 thick dense foam rubber or cork cushions If necessar tern your drives in sound proof well i tern you p ventilated and dust free en 5 Avoid using drives in electricall i i noisy environment with an AC voltaze regulator power controller and Proper DC neutral chassis ground a mn chapter and DC ground wiring electronics 6 To ship drives carefully packa ge them so that the protected from moisture shock and vibration Particularly wi DS drives do not ship with a diskette enclosed but with a thin cardstock cut in the shape of a diskette the only cut out is the cen pad hub hole Ship with a desiccant Also drives that have flip out oors TANDON SHUGART etc must have their doors secured Either tape the doors shut or use a folded piece of cardstock into ris eu Apor grooves Some drives with spring ex rovi i Coy S E EC tor screwing down the cone lever Store drives in a plastic bag with air s ueezed out and cio 7 4 g Wi Ir sq t nd enclose a desiccant To use a long stored drive clean it i X relubricat it 5 1 It if necessary and 8 In finishing alignments and adjustm
160. sen two screws securing the stepper motor body to the drive frame MAKING THE ALIGNMENT CAUTION Before aligning your bad drive verify that all recent diskettes it has Formatted or Written to are Readable by a known ood drive particularly in the inner higher tracks 1f you find that some diskettes are not Readable copy over all of their files to diskettes formatted by a drive from the drive to the drive In most cases a drive with a bad alignment Writes disk that are un Readable to drives with good alignments H you 14 expect that those files will become permanently inaccessible after you ve made your alignment Some folks purposely misalign a drive s in their system to prevent the theft and unauthorized use of files Drive alignment requires concentration steady nerves fine touch and excellent eyesight Do not try to align a drive if you re not up to it rushed or distracted or don t have the proper tools SIGNALS ACROSS THE 717177 READ WRITE HEAD 3 ALL 1 PATTERN CI COARSE STEPPER LLnL LS READ PATTERN S SAE 652 DUAL STEPPER POSITIONING DRIVETEC 320 SUPERMINFLOPPY T sfr rtras hr R W HEAD ALIGNMENT Before starting an alignment be sure that the sensor and end sto are functioning and tight Note that most factory 90 Tk 48 TP drives ca
161. slips off it is stretched Visual inspec tion quickly reveals deterioration If the belt is either deterior ated or stretched it must be replaced deteriorated belt can be temporarily re used if flipped over After replacing or cleaning a belt always re adjust the drive speed PROCEDURES CAUTION Before speed adjusting your bad drive verify that all recent diskettes it has Formatted or Written to are Readable by a known good drive particularly in the inner higher tracks If you find that some diskettes are not Readable copy over all of their files to diskettes formatted by a good drive from the bad drive to the good drive In some cases a drive with a out of spec speed Writes diskettes that are un Readabie to drives with good speed If you don t expect that those files will become permanent ly inaccessible after you ve adjusted speed Some folks purposely maladjust drive speed to prevent the theft and unauthorized use of files Some system makers purposely maladjust speed to prevent the transfer of programs to other systems Before adjusting speed inspect clean and lubricate your drive We prefer to use drive speed software with graphics display to adjust drive speed If you use drive speed software and it indicates that all of your drives are running much too fast or slow the problem could be that the clock in your computer is faster slower than ex pected by the software This will happen if your computer under went a d
162. t 2 s chances Simply by wiggling cables and This spots bad connectors cables contacts leads and solders DISK SERVICE MANUAL III DIAGNOSTICS amp TROUBLESHOOTING 3 Applying gentle pressure can also help detect problem are Apply the pressure using a insulator wooden stick screwdriy handle etc to various parts of the system to uncover bad solde bridge shorts ex solder balls hairs splashes metal burrs and op contacts I start applying the pressure at the corners of the boar I then work inward By doing this if pressure does reveal a bad sp I can zero in on it 4 A similar technique is to use this same insulator to gently tap rap various areas of the board and components This can free an c fending short or re establish a lost contact POWER SUPPLY VOLTAGE CHECK Use your voltmeter to verify and adjust all DC power supply vo ages Are they steady or fluctuate NOTE DC voltmeter me surements do NOT uncover problems due to noisy power supplies logic probe or oscilloscope is required Power Supply noise c come from the AC line the AC regulator or from a DC pow supply Very noisy AC voltage and mild brownouts are frequent many areas and can vary uring the day on a random bas Spills overheating solder defects static discharges impacts a high voltage AC spikes the primary causes of damage to ele tronic components and circuits Another major reason for power supply proble
163. t tape recorder heads are solidly set and that small misalignments aren t critical Head cleaning diskettes com monly cause azimuthal misalignments in Head 1 of DS drives They also tend to wear away drive heads and thus ruin their Read Sensitivity CAUTION Never touch a Read Write head or felt pres sure pad with a hard sharp abrasive or dirty object that includes your fingers Even though most experts insist upon removing the logic board to clean the head s and felt pressure pad I ve cleaned hundreds of heads and pads without doing so Iuse long stem cotton swabs and with the drive door open and diskette removed reach the head and pad at about a 45 degree angle between the logic board and frame most drives For your first time a snorkel neck penlight flashlight can save you a lot of extra disassembly to find the head But you quickly learn to do by feel alone The head is usually more accessible by Stepping or sliding it manually to its innermost tracks You can sa ely and easily manually slide the head carriage assembly only on band actuated drives In lead screw drives you can safely manually rotate the stepper motor shaft to move the head In spiral wheel drives you can safely rotate the spiral wheel to move the head First spray a cotton swab with the SPRA KLEEN then run or pat the swab about a dozen times over the head s and pad Using a fresh swab repeat the process with the alcohol CAUTION Any rough motio
164. th use similar basic drives Logic Boards are different Both are seriai H drives Neither uses a Sector Index Optical Coupler je arive py disk FATUR SAS p Li 3 i 4 e lt 2 7 EM eee ere Chapter VIII ELECTRONICS amp REPAIRS DRIVE POWER amp GROUNDING Correct power wiring and grounding of computer systems is critical and should be carefully observed If you ve ever typed in hours of boring data only to see it flushed down the toilet by one power glitch you now have an intense appreciation of proper power and ground wiring The following figures describe the power and ground wiring scheme we most prefer You may want to go as far as installing an UPS system This re quires a of batteries battery trickle charger and inverter to change the DC back to 120 VAC These systems can run into the 5 Thousands POWER SUPPLY ADJUSTMENTS At st once a year verify the drive s DC voltages and adjust theas necessary 5 and microfloppy drives require 5 logic and 12 VDC motors 8 drives also require 120 or 280 and 24 VDC and some require 5 VDC Turn ON the drive and run until warm Turn OFF power and remove drive enclosure pot s in the external drive power supply power supply Board rear of drive or power section of the logic board are usually installed to adjust VDC voltage lev
165. the head is displaced one or more integer tracks from each other and are neither drive nor drive utility software compatible Some DDA packages may not detect displaced but aligned tracks and will OK two perfectly aligned drives that are not physically compatible with each other due to the difference in head physical positions for T00 5 Most systems that run their controllers from real time clocks 60 Hz tine frequency are not supported by DDA software because proper index timing resolution for accurate speed and index timing adjustments is not possible 6 We have not found DDA package that directly tests the 00 sensor and end stop What is required is continuous stepping back and forth between 00 and T01 T02 or T03 so that the TO sensor and or end stop can be precisely adjusted 7 Few DDA packages provide actual access time information This is usually expressed as the amount of time but sometimes as the actual number of attempts to load a set program track or Sector and is intimately related to drive actuation method head alignment hysteresis clamping Read Sensitivity and diskette quality Armed with such a capability one would have a powerful tool for evaluating both drives and diskettes for quality J amp M SYSTEMS DDA We fully evaluated the J amp M SYSTEMS LTD DDA software of Most o our comments below aiso which we have mixed feelings apply to DDA software in general ua tg E E
166. top then adjust 1 degree CCW Again make a fine mark with this felt tip pen Now continue adjusting CCW 1 degree between the two alignment marks at a time until you are exactly J terpoint between the first outer and The objective is to find the cen misalignment positions NOTE In motor aligned drives when you loosen the motor screws maintain a comfortable hold on the motor Do NOT allow the motor to sag or shake Should you wish to remove your hand from the motor retighten its screws to snug first or motor screws to snug NOT tight and then retest with DIR If alignment shifted which sometimes happens repeat the alignment procedure until new correct aligned position is found Continue the tightening of the screws and the retesting with DIR N until the screws all tight and you get reliable DIR Ns The secret to loosening and tightening screws is to gradually loosen or tighten them in rotation imilar to vehicle motor head bolts if you completely loosen some screws while leaving others tight or Vice versa you can warp the frame and cause misalignment Do not overtighten the screws as they may shear off or warp the drive frame Tighten just beyond snug Then after the alignment has been set and verified apply fingernail polish to the edges of each screw Tighten all module assembly If while proceeding with your CW adjustment you encounter a stop return to near your start position then turn
167. trate file transferal between them and other similar systems Re adjusting drive speed up to rated speed makes the drives unuse able by these systems Drive speed out of adjustment usually combines with radial and azimuthal misalignment clamping eccentricity hysteresis and Read Sensitivity problems to produce errors That s why two drives of the same model in the same system may vary widely in their tolerances to speed out of adjustment TANDON drives the speed pot is blue and is located facing towards the logic board on the servo motor board rear of drive and is difficult to reach In our TANDONs we ve drilled 3 8 Mt mn Bm mi intel ane i o mma e n ue DISK SERVICE MANUAL 4 1 hole the bus extender board to get a better adjustment angle In TEXAS PERIPHERAL drives the speed pot is on the logic board left facing front In MPI drives the speed pot is also on the logic board See photos for placements of some speed pots Do not adjust a pot on the logic board unless you are certain that it is the speed pot particularly a pot with loctite or paint on its adjustment screw unless you keep track of your precise starting oint On some drives the speed pot can be reached through ole in the bottom or back the drive others require enclosure removal Be sure to use a plastic ajustment tool or a screwdriver with all of its shaft covered by
168. u will Don t panic if flip out type drive door breaks TANDONs SHUGARTs These doors are easy to replace if you have spare one Remove the drive enclosure Unscrew the 2 phillips Screws attaching the metal plate latch inhibitor and door neche anism to the cone lever assembly Remove the old door from behind the front panel Remove broken pieces that may have fallen into the drive Insert the new door the same way being sure to insert the door posts into the 2 front panel guide slots Re attach the door and metal plate to the cone lever assembly Do not tighten the screws yet Lubricate the door front panel slots and door hinge with vegetable oil Work the new door back and forth with an inserted diskette to assure proper fit Read Directory each time the door is closed to assure proper diskette seating While the new door is closed on a diskette tighten the screws Read Directory again to verify Re install the enclosure It may be easier to work if you swing away the logic board and or remove the front panel The front panel is secure by two phillips screws on the pully side of the drive When you re attach the front panel GENTLY tighten these screws as they can be easily stripped out Flip out doors on TANDON and SHUGART drives are some what interchangeable This means they ll work OK but may not perfectly fit You can temporarily operate a flip out door drive without the door Two ways 1 While accessing t
169. uter equipment Keep all small metal items staples paper clips screws nurs metal shavings away from computer systems Always cover t drives with a lint free cover after turning them OFF In fact cover ALL computer eguipment when not in use Equipment exposed to normal office and househoid air pollutants collect a iot of dust id year s time and the lubricants dry out Dust and smoke are gear on drives and diskettes because the particles get onto the Read DISK SERVICE MANUAL III H 1 recording sur th sandpaper any connector or a drive or system ystem repair work without first turn ing OFF power to the system Entire Computer Systems were de stroyed simply because someone moved a Connector with system power ON When removing or replacing connectors do so Zantiy irmly and uniformly Do not force a connector force can dam age or short contacts Before turning power ON b connectors are solidly and sure that ALL non gold plated printed circuit board edge nectors cleaned every time preventive maintenance is done on the system Use a pink not white pencil eraser to remove an oxide from their contacts Thoroughly clean al eraser debris The drive cable mods have gold contacts e extra careful when connecting and disconnectin power sup lies and while working in the vicinity of power i MUST be OFF and the By bend supplies powe
170. wama unun amam wass Tuma ensi SD SS A A SL 100 ms MIN MOTOR ON N77 777 FD179X BLOCK DIAGRAM WESTERN DIGITAL POWER E 100 ms MIN DRIVE SELECT 500 ms MIN 25 MIN VALID READ DATA 1 1 ms MIN SIDE SELECT 200 5 MIN o 100 5 MIN E Ams WaT BATE 500 NS MIN M 3 ys MAX TRANSITIONS READ TO WRITE SHUGART ASSOC POWER ON SELECT 1 MIN DIRECTION 14s MIN 5 1 as MIN POWER ON TO STEP SHUGART ASSOC asm w wama tasa sana GIN uman usan mam i M 100 ms DRIVE SELECT 500 ms MIN MIN suam vnd sona um eu MR asun waqa GREG QR uapa CURE RERO Saman GER Gham RUNS uama NEAR anam muna MOTOR ON ORIVE SELECT 500 Ns VALID WRITE 2 5 MIN 200 MIN SIOE SELECT to VALID READ DATA VALID READ DATA ee 18 ms MIN 500 NS MI PERY MIN WRIT
171. ws are lo inthe rear or rear side of the drive in most drives The uova x 2 may pe a cam screw NOTE The sensor and end n although interrelated are two separate adjust ments Adjust only the one s that needs to be adjusted bon need to be adjusted adjust the end stop first Some 0055 don t rely upon the sensor for d i i 00 52 ee when the head is on T00 by heads the ID oweve i i i required to boot the drive and to ormat Some drives do NOT come with a sensor but onl Ish ip conte head travel APPLE Unt COMMODORE ei adh manufactured by ALPS and NEWTRONICS are CHAPTER CONTINUED AFTER PHOTO SECTION VII 4 J aquya osa le tud au Spy RAB n z DISK SERVICE MANUAL ABOUT THE PHOTOGRAPHS The drives pictured herein are representative of almost all floppy drives now in popular use They include standard bus 5 8 and microfloppy drives as well as some special drives ex APPLE COMMODORE SONY There are hundreds of different drive models far too many to picture one here If your particular drive model is not shown by studying these photos and your drive s anatomy and operation you should be able to locate all important anatomical features ex R W Head TOO Sensor and End Stop Write Protect Detector Sector Index Optical Coupler TRN mo tors Spe
172. xisting file during READ WRITE Shame on An error resulted An error resulted during a oul 6 DIRECTORY SPACE FULL FULL DIRECTORY The Directory has no more room on it to logn a new file even though the diskette may have room for the new ile s data PROGRAM TYPE ERRORS 1 ILLEGAL FILESPEC tained illegal characters 2 FILE or PROGRAM ACCESS DENIED IMPROPER ACCESS CODE or PASSWORD ACCESS TO PROTECTED FILE DENIED You tried to access a protected file or program by not using a password or access code or by using an incorrect one DISK ETTE SPACE FULL diskette is filled up fit no more file data even though its Directory may have room to log in the 4 PAST EOF or END OF FILE Results from trying to Read Write beyond a file s EOF Immediately CLOSE the file 5 EOF ENCOUNTERED The byte record just accessed was the EOF byte record Usually results when trying to Read a file that was created for later storage but is still empty 6 FILE or PROGRAM NOT FOUND sought file or pro gram was not found 7 ILLEGAL DRIVE NUMBER The drive number in the file spec indicated a drive not permitted by the DOS drive configura tion parameters or by the system 8 LOAD FILE FORMAT ERROR attempt was made to Load non object code in the command mode 9 FILE PROGRAM DELIMITERS TOO FAR APART at tempt was made to Load object code or a data file as a BASIC pro gram
173. y proper spindle motor and servo motor board connections P13 P20 and P21 D Defective Spindle Motor Replace spindle motor Insert diskette in Verify connecticn to logic Repair or replace index sensor Replace index sensor LED and or See speed adjustment x aaah maA gate dna tg aa Van Nal AANS n cad cde R io RR um z 3s DISK SERVICE MANUAL DIAGNOSTICS amp TROUBLESHOOTING E Defective Spindle Assembly Repair replace spindle as sembly F Bad Spindle Motor Electronics Replace or repair servo motor board or logic board if drive has no servo motor board 3 WILL NOT SEEK OR RESTORE A Controller Malfunction Verify controller Direction Step and Select signals B Disconnected Stepper Motor board P12 C Defective Stepper Motor Verify that a a loose part is not binding stepper motor or hea ace stepper motor or module assembly Replace or repair logic Verify connection to logic Rus tail defect or carriage assembly RS board 4 NO WRITE A Controller Malfunction and Write Data signals Head s Or Write Protect Switch Disconnected Verify nections to head s P5 and to write protect switch P8 C Write Protect Switch Maladjusted Verify write protect switch operation D Defective Head s Replace head s or module assembly E Defective Logic Replace or repair logic board F Poor Complian

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