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Tandon TM50 Service Manual

1. 1 1 7 e a Xx ANGULAR Zu HE J BREAK ALL SHARP CORNERS APPROX oi 2 MODEL M READ WRITE BOARD DOUBLE SIDED cl 2 044 Donor scar 9 2 TM 50 SCHEMATIC 1 D REVISIONS DESCRIPTION PRELIMINARY RELEASE PRE PROD RELEASE PER 2 1271 _ L C TABLE PIN LIST PRE PROD RELEASE 128 0 UI 592 NAME t OF PINS USE REV PER EO 2970 REV PER EO 3 7406 10 HEAD ose 907 2 POWER Rev PER 3301 5 7406 INCORP EO 2038 7400 7404 UB 7400 Us 1 393 T SPARE GATES IC QTY 019 APPLICABLE REV LEVEL APPLICABLE ASSY REV LEVEL COLORS REFER 70 HARNESS WIRING AL t DIODES ARE 1N 4 4 4 6 b THE INFORMATION CONTAINED 5 THE PRO CAPACITORS ARE IN CREE 10 Tandon ALL 17 RESISTORS ARE 8 W romney SPICE RESISTORS ARE N OHMS 7 4 5 DIMENSIONS ARE IN INCHES ica mauan MODEL TM 5O n p La READ WRITE BOARD ror x A ALL ODD NUMBERED PINS ARE CONNECTED TO GROUND SCHEMATIC pups DOUBLE SIDED 10441 NOTES UNLESS OTHERWISE SPECIFIED wee 2 7 4 o eren e 7 9 4 REVISIONS REV DESCRIPTION DATE DR RP2 SEE SHT 1 150 4 INDE
2. 4 a Ww SECTION 5 CONTENTS Title Motor Select Jumper e s e e Write Protect Wl s Head Type W2 W3 s s s s vai Re W4 Through W8 AWO mp ee Motor On Diskettes 4 um den 80 0 Loading The Diskette 4 Write Protect Tab word we DS gt Diskette Handling and Storage ea Mr e THEORY OF OPERATION Introduction m e IIT e cw gel css Data Recording e a e 4 Components Of The Drive Generate and Interpret Control Signals Index Sensor e e Write Protect Switch e e Track 0 SensO w ec DRIVE SEE CEL x es x tae 0 Read Write Head Positioner Step DIre ecti n u a od xe Stepper Motor Control Ts Stepper Motor on Read Write ae s a e e e e o s s s o Read Write Head Assembly gt Side Select Circuits e Write Erase Circuits s e e e e Read Data Circuits w s s Spindle Control a voe 58 Spindle Motor and Spindle Assembly Spindle Motor Enable Circuit e Spindle Motor Control Circuit Diskette Enabled Switch Door Lever MAINTENANCE CHECKS AND ADJUSTMENTS INCrOdUGELO sian
3. 4 1 4 2 FM Recording Magnetization Profiles 4 2 4 3 Read Timing Diagram s e s e e e s s e e s a 4 2 4 4 Interconnect Block Diagram e 4 3 4 5 Soft Sectored Index Pulse s s so 4 5 4 6 Track e e we mA Xe Se D SE 84 voce 4 6 4 7 Write Data Circuit Block Diagram a o 4 10 4 8 Write Operation Timing Diagram s e s e 4 11 4 9 Read Circuit Block Diagram a s s s 4 13 4 10 Servo Circuit Board 4 14 5 1 Logic Circuit Board With Test Points Be el ee is 5 2 5 2 Write Protect Switch Adjustment 5 5 5 3 Location Of R15 Speed Control Potentiometer 5 6 5 4 Bottom View Of Drive s v w on 5 6 5 5 Hub Center Line and Track Location 5 7 5 6 Cats Eye Patterns X 6 94 4 00 404 5 8 5 7 Stepper Motor Retaining Screws and Camming Bars 5 10 5 8 Index To Data Pulse ss s s m 5 11 5 9 Index Sensor s Retaining Screw and Adjustment 5 12 5 1 Optimum Head Azimuth Alignment e 5 14 5 1 C Head Azimuth Alignment Of Acceptable Lower Limits PPP 5 14 Head Azimuth Alignment Of Acceptable Upper Limits a e s oac e wow wo 5 15 Stepper Motor s s ss on Upper Plate ae ee 6 13 Track 0 Sensor and Stop Block 6 15 Drive 4
4. cac d aiite nsum MAGNETIC ELEMENTS _ 3 EE I i t i t m FIGURE 4 2 FM RECORDING MAGNETIZATION PROFILES As the disk spins the magnetic fields of the stored data pass successively under the head The changing fields induce in the head an A C voltage signal which is then amplified and filtered differentiated and digitized Figure 4 3 The comparator and the digitizer circuitry generate a one microsecond Read Data pulse corresponding to each peak of the Read signal Then the composite read data signal is sent to the user system via the Read Data interface line LINEAR OUTPUT FROM FILTER OUTPUT FROM DIFFERENTIATOR READ DATA INTERFACE FIGURE 4 3 READ TIMING DIAGRAM HEAD f CONTPOL AND READ WRITE CIRCUIT BOARD INDEX INDEX EMITTER SENSOR P12 712 1 2 MOTOR CONTROL INTERFACE J10 I O 1 6 INTERFACE J8 J9 1 34 1 4 INDEX DETECTOR SPINDLE MOTOR ACTIVITY LED E SERVO CIRCUIT BOARD STEPPER MOTOR CONTROL DISKETTE LOADED FIGURE 4 4 INTERCONNECT BLOCK DIAGRAM 4 3 4 2 COMPONENTS OF THE DRIVE The avi contains the e
5. THE SECOND ONE IS THE TRACK 0 STOP BLOCK Installation 1 Position the Track 0 sensor over the retaining holes in the chassis Insert the retaining screw into the sensor toward the front of the drive Insert the screw through the Track 0 stop block and into the rear retaining slot of the Track 0 sensor Slide the Track 0 stop block toward the rear before tightening the screw Route the cable for the Track 0 sensor back to the control and data circuit board Apply tie wraps as required TRACK 0 SENSOR CHASSIS CAMMING 5 TRACK 0 STOP 7 BLOCK FIGURE 6 8 TRACK 0 SENSOR AND STOP BLOCK 6 15 HEAD MODULE Removal Remove Remove Remove Remove Remove At the the the the the the data and control circuit board chassis shielding power input plug stepper band Track 0 sensor rear of the drive remove the V spring which holds two grooved rails Raise the head assembly slightly removing it toward the rear of the drive NOTE FROM THE REAR OF THE DRIVE THE RAIL ON THE LEFT HAND SIDE IS ENCASED BY THE HEAD ASSEMBLY CASTING THE RAIL HAND SIDE ON THE RIGHT IS RIDING ON THE GUIDE Installation l Position the head assembly to slide over and around the guide rails if the V spring clip still has the front of the guide rails attached to the chassis Insert the clip into the grooves of the rails and the retaining block on the chassis Slide the hea
6. A true low level on this line selects the read write head on side one the upper head of the drive Output Control Lines Index Sector The index sector signal iS composite of the index pulse and sector signals An index pulse is provided once every revolution 200 milliseconds nominal to indicate the beginning of a track to the controller The leading edge of this signal must always be used to ensure timing accuracy The index sector line remains in the true low state for the duration of the index pulse which is nominally four milliseconds The sector signal portion appears only when using hard Sectored diskettes Track 0 When the drive is selected the Track 0 interface signal when true low indicates to the controller that the read write 5 are positioned at Track 0 This signal remains true low until the heads are moved from Track 0 Write Protect When the Write Protect line goes true low the diskette is write protected and the write electronics are disabled It is recommended the controller not issue a Write command when the Write Protect signal is true low When the Write Protect line is false high the write electronics are enabled Composite Read Data This interface line transmits the readback data to the controller when the drive is selected It provides a pulse for each flux transition detected from the diskette The Composite Read Data output line goes true low for a duration
7. Figure 4 7 The signals required to control the data electronics provided by the host controller are 1 Drive Select 2 Write Enabie 3 Write Data 4 Side Select The winding on the head is center tapped During a write operation current from the write current Source flows in alternate halves of the winding under control of the write waveform yenerator When the drive is selected and write protect is false N Write Enable initiates the write logic Seven events that occur are Figures 4 7 and 4 8 1 The pre erase delay one shot is started 390 microseconds 2 post erase delay shot is started 900 microseconds 3 The post erase delay one shot outputs a signal N Internal Write Busy It is used to disable the Read Data output circuit NWRT to increase the read write diode matrix voltage from 5 volts D C to 12 volts D C via the side select logic during a write operation 4 The write current source is enabled via U4 5 The write waveform generator has its preset and clear inputs set to 5 volts D C instead of ground optional 6 Input diodes to the read amplifier are reverse biased by N Write to protect the read amplifier during the write operation 7 The write data input is inverted and used to clock the waveform generator which selects a write driver thus providing a ground to forward bias a diode allowing current to flow through the coil N WRITE SIDE SELECT BUFFER N WRITE DAT
8. Test Point 5 Ground Test Point 8 or 14 Read Differentially A plus B B inverted Time Base 20 milliseconds per division External Trigger Test Point 12 positive edge Adjust amplitude for at least four divisions on the oscilloscope A C coupled Apply power to the drive 5 7 EVEN AMPLITUDE 100 LEFT 30 OF RIGHT LEFT 80 OF RIGHT LEFT 40 OF RIGHT 80 OF LEFT RIGHT 80 OF LEFT RIGHT 40 OF LEFT HT FIGURE 5 6 CATS EYE PATTERNS 5 8 10 li 12 13 14 15 16 17 18 19 20 21 NOTE THE TRACK 16 RADIUS IS 1 9167 INCHES FROM THE CENTER OF THE HUB OTHER TRACK LOCATIONS ARE COMPUTED BASED UPON 48 Select the drive Insert a certified alignment diskette Dysan Number 224 2A into the drive Select Head 0 the lower head Read Track 16 for Radial Track alignment of the lower head Adjust the oscilloscope to observe a Cats Eye pattern Figure 5 6 Verify the smaller of the two Cats Eye patterns is not less than 75 percent in amplitude of the other one NOTE THE 75 PERCENT FIGURE IS FOR USE WITH AN ALIGNMENT DISKETTE VERIFIED AGAINST A STANDARD ALIGNMENT DISKETTE Step the drive to Track 0 then step it back to Track 16 Verify the Cats Eye pattern Step the drive to Track 26 or higher then step it back to Track 16 Verify the Cats Eye pattern Switch to Head 1 the upper head Read Track 16 to verify the alignment of the upper head if a
9. a a f Cre s RO QC VR Visual Inspection e a 4 Equipment Required a s e e gt o Power Drive Select Check a s e o Write Protect Switch Check and Adjustment Write Protect Switch Check Write Protect Switch Adjustment a Drive Motor Speed Check and Adjustment Drive Motor Check e e s e o Drive Motor Adjustment e so a e a o ii Page Number 3 11 3 11 3 11 3 11 3 11 3 12 3 12 3 12 3 13 3 13 1 1 I gt gt pe gt RHEE EEE Ph PRE DE dd 4 14 uU uu 1 I t Oe PPR e 1 Section Number 5 6 Unc 5 10 5 11 5 12 5 13 6 APPENDIX APPENDIX CONTENTS Title Radial Track Alignment Check and Adjustment Radial Track Alignment Check Radial Track Alignment Adjustment index Checks and Adjustment e s a Index To Data Pulse Checks a Index Sensor Adjustment s Azimuth Check Track 0 Sensor Check and Adjustment 4 Track 0 Sensor Check Track 0 Sensor Adjustment Track 0 Stop Adjustment Head Output Check Cone Centering Check Compliance Check and Adjustment Single Sided Drive Compliance Check 5 Complia
10. NINTWRTBSY NWRT ea RPIO OAMATION HEREDON IS THE PAD NOTES UNLESS OTHERWISE SPECIFIED TORES PERTY OF TANDON CORPORATION MO PORTION OF THIS DATA SHALL BE RELEASED DISCLOSED USEO OR CORPORATION UNLESS OTHERWISE SPECIFIED DIMENSIONS ARE IN INCHES TOLERANCES anguran irm x PROJ ENGA APPROX 010 4 A 3 DATE Tandon CORPORATION EL TM 50 WRITE BOARD SCHEMATIC DOUBLE SIDED d READ FINISH EHE IDENT NO DWG NO REV 210441 M REVISIONS 45v REV DESCRIPTION DATE 12 5 12VS SEE SHT i 1 RPS ev 3 5 6 2 D NWRT 25 27 B 2 3 7406 7406 750 45v ECRI 5V 0342835 2 2 75 rei R24 Of 48 150 IK RP3 recom 10 3 Dog 2 750 N SIDE o gt 7406 7 ONE w9 7406 bz 02 5 7406 7406 RPS ee 46 7 3 D 4 750 R20 cT d 26 2 3 c 4 P e 8 2K 8 2K 5V RPS IK CR 9 CATHODE PER gt 3 b 4 CATHOD 2474055 RPS 2 RPS 12 5 R23 9 1 04 UA 3146 5 s SIN 3146 3 7406 CP cig 5 5V 6 4 150 RPG cys Rid 13 168 nr NWRT gt CRIB DATA 7406 7406 2 75 7406 RIZ 52308 270 9 NWRT ais 12VS o
11. PLATE ASSEMBLY DO NOT BEND THE UPPER ARM OF THE HEAD ASSEMBLY SINCE DAMAGE CAN RESULT Installation 1 Position the upper plate assembly with the lift plate under the upper arm of the head assembly and the mounting holes lined up to the chassis Insert three Number 1 Phillips screws two at the front the drive and one at the rear of the drive by the drive motor Apply four inch pounds torque maximum to the screws NOTE LEAVE THE MOUNTING HOLE ON THE POWER INPUT PLUG SIDE OF THE UPPER PLATE ASSEMBLY EMPTY THE CHASSIS SHIELDING RETAINING SCREW USES THIS HOLE Replace the spring on the lift plate ot Route the lower index assembly throuyh a hole in the chassis and mount it on the bottom of the drive Route the cabling using the tie wraps provided Replace the servo circuit board Replace the front panel Replace the diskette lever assembly Replace the chassis shielding Replace the control and data circuit board MOUNTING SCREWS LIFT PLATE SPRING FIGURE 6 7 UPPER PLATE ASSEMBLY 6 13 TRACK 0 Removal SENSOR AND TRACK 0 STOP BLOCK Remove cable Plug P9 from the control and data circuit board Remove the tie wraps as required to free the cable to the sensor Move the head assembly toward the spindle Remove two Number 1 Phillips screws from the Track 0 sensor Figure 6 8 NOTE THE SCREW TOWARD THE REAR OF THE DRIVE IS GOING THROUGH TWO PIECES ONE IS THE TRACK 0 SENSOR
12. REVISIONS DESCRIPTION REV DATE OR CHK APPR REVISED PER 13004 REVISED EO 13195 E ERGY 6 REVISED PER EO 13206 al ue H_ REVISED PER 13386 KORE X PRODUCTION RELEASE ED 40480 1 555 LIST CONTROL DISKETTE LOADED FOR PART NUMBER VALUE USAGE OF COMPONENTS n AFFECTED BY VERSION NUMBER SEE TABLE T 5 USED FOR TEMP 4 ALL DOES ARGE DIMENSIONS ARE IN INCHES TOLERANCES IN 4446 CAPACITORS ARE INMF t 207 m 2 1 Resistors V sheik sine Goosen ALL RESISTORS ARE IN OHMS 4 5 ANGULAR aam APPROX 010 NOTES UNLESS OTHERWISE SPECIFIED EOC 041 8 81 2 Tre NO SIGNATURES DATE Tandon etree ca n CORPORATION PROJ ENGA MODEL TM SO MOTOR CONTROL SCHEMATIC FINISH MATL SIZE IOENT DWG NO REV 210439 Kone 0 HI U6 10 13 edo SP NDLE MOTOR D 4 3 8 3 J2 TK 5VvV cl 3 F 47 12 4 12V 3 G2 Jl 2 4124 R9 R2 AS 20K YEL 4 022 5V i REA 1K 1 2 8 RP3 RP3 257 27K 7406 DISKETTE JS Sarde ENAB WHT 29 SWITCH gt 7406 4
13. are acceptable TRACK 9 8 SENSOR CHASSIS CAMMING TRACK 0 BLOCK FIGURE 5 13 TRACK 0 STOP Remove the alignment diskette and insert a nonwrite protected diskette into the drive Set up the oscilloscope Channel A Test Point 4 Channel B Test Point 5 Vertical Amplitude 50 millivolts per division Ground Test Point 8 or 14 Read Differentially A plus B B inverted Time Base 20 milliseconds per division External Trigger Test Point 12 Seek to Track 39 Write 2F all ones pattern on Head 0 Verify the amplitude is 200 millivolts or greater peak to peak Write a 2F all ones pattern on Head l Verify the amplitude is 200 millivolts or greater peak to peak 5 18 5 12 CONE CENTERING CHECK Cone centering is the ability of the cone clamping mechanism to center the diskette on the hub causing it to rotate concentrically This check and adjustment should be made whenever the upper plate assembly has been removed or replaced If the cone centering cannot be adjusted verify the measurement with a second diskette 1 Set up the oscilloscope Channel A Test Point 4 Channel B Test Point 5 Vertical Amplitude 100 millivolts per division Ground Test Point 8 or 14 Read Differentially inverted Time Base 20 microseconds per division External Trigger Test Point 12 positive edge 2 Apply power to the drive 3 Select the drive 4 Seek to Track 0 5 Write 2F pattern on
14. band onto tne tension plate remove the pressure from the plate The stepper band seats itself around the stepper motor shaft Move the head assembly to obtain the maximum length of travel while watching the stepper band on the stepper motor shaft If it maintains a straight path it is o not relax the tension plate and try to smooth out the stepper band CAUTION TIGHTENING THE SCREW TOO TIGHT WILL BEND THE STEPPER BAND CAUSING IT TO NEED REPLACING When satisfied with stepper band operation snug up the stepper motor shaft screw to four inch ounces of torque Replace the power input plug Replace the chassis shield Replace the control and data circuit board STEPPER Removal 7 FIGURE 6 5 E STEPPER BAND drive has a wire wrap covered wraps Cut the two tie wraps MOTOR Remove the control and data circuit board Remove the chassis shield Remove the stepper band Remove the stepper motor cable plug P3 from the servo circuit board Remove the two Number 1 Phillips screws on the bottom of the drive one at each end of the stepper motor The screw toward the front of with shrink tight and two tie Remove the stepper motor from the chassis Installation l 2 Position the stepper motor shaft through the hole in the chassis Insert retaining screws and washers The retaining screw toward the front of the drive Shrink tight has a wire wrap covered with Route excess wiring
15. close to the limits the suspected fault is normally caused by some other problem Completing other checks and adjustments may disclose the actual problem Refer to the schematics in the appendices and the theory of operation in Section 4 for circuit descriptions Test point location is illustrated in Figure 5 1 5 1 VISUAL INSPECTION Before applying power to the drive or doing any checks or adjustments visually inspect the drive 1 Check for loose or missing hardware 2 Ensure the front latch opens and closes The head arm raises when the door is opened 3 Ensure the front panel is secure 4 Manually rotate the drive hub It should rotate freely 5 Ensure the circuit boards are secure 6 Ensure the connectors are firmly seated and installed correctly 7 Check for damaged or missing components on the circuit boards 8 Ensure that a diskette can be inserted and removed easily HSNO WNP a TM50 TEST POINTS 12 volts D C 8 Ground Write Protect Switch 9 Read Data To Interface Motor On From Interface 10 Track Zero Read C ll Step Read 12 Index Read Differential 13 Select Read Differential 14 Ground FIGURE 5 1 LOGIC CIRCUIT BOARD WITH TEST POINTS 5 2 EQUIPMENT REQUIRED The following equipment is required for checks and adjustments 1 2 duai channel wideband oscilloscope Hewlett Packard Model 1740A or equivalent An exerciser AVA Model 103
16. drive select producing an output signal on the interface Track 0 Sensor The Track 0 sensor signal is derived from an infrared L E D and phototransistor internal to the drive As the head carriage moves back toward Track 0 the sensor is activated between Tracks U and 2 This low active signal comes via J9 Pin 4 It is inverted by 09 The combination of the Track 0 sensor being activated and the proper stepper motor phase Phase 0 produces a low output at IC U8 Pin 6 Test Point 10 This signal is buffered through IC 017 Pins 9 and 8 to be gated with drive select at IC U18 Pins 9 and 10 to give a Track 0 output to Pin 26 of the interface After 017 Pin 8 this signal is gated with direction 07 Pin 12 at IC U6 Pins 12 13 06 Pin ll when true low inhibits stepping to Track 0 minus 1 6 VOLTS TRACK 0 TEST POINT 10 oe 8 VOLTS TRACK 0 ADJUSTMENT MONITOR POINT IC 08 PIN 4 4 3 2 1 Bean 1 2 3 4 8 8 doo PHASES 0 1 0 1 9 1 FIGURE 4 6 0 Drive Select The Drive Select signal is derived from the host controller through the interface connector R39 holds the output of the appropriate select line high until the line is driven low The signal is buffered through 017 which enables the drive s electronics The front panel L E D physically located on the drive motor s servo circuit board is dri
17. end of the post erase delay and keeps 12 volts D on the read write diode matrix during the erase time The duration of a write operation is from the true going edge of write Enable to the false going edge of Trim Erase This is indicated by the Internal Write Busy waveform Figure 4 8 Read Data Circuits The read electronics consist of l Read Only and Side Select circuits 2 Read Amplifier and Linear Phase Filter 3 Differentiator 4 Comparator Time Domain Filter and Digitizer The Read Only circuits are used to isolate the read amplifier from the voltage excursion across the head during a write operation The side select is used to enable one of the read write head s The drive must be selected by the user s system before reading can begin In addition to the requirements established in this section a 100 microsecond delay must exist from the trailing edge of the Trim Erase signal to allow the read amplifier to settle after the transient caused by the Read Only circuit returning to the Read mode The output signal from the read write head is amplified by a read amplifier and filtered by a linear phase filter to remove noise The linear output from the filter is passed to the differentiator which generates a waveform whose zero crossovers correspond to the peaks of the Read signal Then this signal is fed to the comparator time domain filter and digitizer circuitry Pigure 4 9 4 6 SPINDLE CONTROL The components of the
18. of 1 0 25 microseconds for each flux change detected from the diskette The leading edge of the Composite Read Data output pulse represents the true position of the flux transitions on the diskette s surface Typical Interface Characteristics Lines between the controller the drive have the following characteristics Vout True 0 4 volt maximum at Dude 48 milliamperes maximum Vout False 2 4 volts minimum open collector at Ig 250 microamperes maximum Figure 3 1 contains the characteristics of the electrical interface Figure 3 2 contains the control and data timing requirements 5 VOLTS 150 OHMS 74LS04 OR EQUIVALENT TRUE 7438 OR EQUIVALENT TRANSMISSION LINE x 10 FEET FIGURE 3 1 ELECTRICAL INTERFACE CHARACTERISTICS 3 5 D POWER D C power is supplied to this drive via a four pin AMP connector J7 connected to the rear of the drive The mating connector not supplied is AMP Part Number 1 480424 0 using AMP contact Part Number 606191 1 Pin assignments are found in Table 3 2 The chassis should be connected to earth ground to ensure proper operation TABLE 3 2 POWER CONNECTOR PIN ASSIGNMENTS ly Voltage 12 volts D 12 volts return 5 volts return 5 volts D C Ground lug 3 16 quick disconnect Chassis ground from controller 3 6 DRIVE ADDRESS AND OPTION PATCHING The drive address and opti
19. structures with a life expectancy of 20 000 operating hours Operator access for diskette loading is provided via a horizontal slot located at the front of the drive The electronic components of the drive are mounted on two printed circuit boards The logic circuit board is mounted above the chassis The motorcontrol circuit board is mounted on the bottom of the chassis Power and interface signals are routed through connectors plugging directly into the logic circuit board 1 3 FIGURE 125 SECTION 2 PRODUCT SPECIFICATIONS INTRODUCTION This section contains the mechanical electrical and operational reliability and environmental specifications for the 50 1 and TM50 2 drives MECHANICAL SPECIFICATIONS The physical dimensions of the drive are located in Figure 2 1 ELECTRICAL AND OPERATIONAL SPECIFICATIONS The electrical and operational specifications are located in Table 2 l RELIABILITY SPECIFICATIONS The reliability specifications are located in Table 2 2 ENVIRONMENTAL SPECIFICATIONS The environmental specifications are located in Table 2 3 TANDON CORPORATION CHATSWORTH CALIFORNIA 91311 179DDD 001 REV A 1 625 is 00 203 20 MM 6 32 769 95 53 A 342101 dy 1875 625 lt i 41 27 MM xo VIEW PCBA NOTES 1 DIMENSIONS ARE GIVEN IN INCHES METRIC EQUIVALENTS ARE IN PARENTHESES 2 TOL
20. trim erasure of data Industry Standard Interface Compatibility The drive is compatible with controllers that use an industry standard interface Track 0 Sensor The Track 0 sensor is provided to generate a logic level at the drive interface indicating that the read write head is positioned at the outermost track Index Sensor An index sensor is provided to generate electrical pulses at the drive interface coincident with sensing Index Sector holes on the diskette Activity Indicator An activity indicator located on the front panel is automatically illuminated when the drive is selected Compact Size The reduced height of the drive enables it to occupy only one half the mounting space required for a conventional drive 1 4 FUNCTIONAL DESCRIPTION The drives are fully self contained and require no operator interven tion during normal operation Each drive consists of a spindle drive system a head positioning system and a read write system When the front latch is opened access is provided for insertion of a diskette The diskette is held in place by plastic guide rails Its location is ensured when the diskette is inserted until a back stop is encountered and the ejection mechanism latches Closing the front latch activates the cone clamping mechanism resulting in accurate centering and clamping of the diskette The drive hub is held at a constant speed of 300 RPM by a servo controlled D motor The head s remai
21. 2 500 kilobytes per disk D C Voltage and Current Requirements 5 volts C Power 5 volts 0 25 volt at 800 milliamperes maximum with less than 100 millivolts peak to peak ripple 12 volts D C Power 12 volts 0 6 volt 1 3 amperes maximum surge for 50 milliseconds 800 milliamperes average Shipment When prepared for shipment by Tandon the drive meets the requirements of NSTA preship ment test procedure Project 1 TABLE 2 2 RELIABILITY SPECIFICATIONS Error Rates exclusive of external sources g electronics defective and contaminated diskettes Soft Errors Recoverable One in 10 bits Hard Errors Nonrecoverable One in 1012 bits Seek Errors One in 109 seeks Mean Time Between Failures 8 000 hours 25 percent duty cycle Mean Time To Repair 30 minutes TANDON CORPORATION CHATSWORTH CALIFORNIA 91311 179DDD 001 REV A TABLE 2 3 ENVIRONMENTAL SPECIFICATIONS Temperature Operating media dependent Nonoperating Relative Humidity Operating noncondensing media dependent Nonoperating noncondensing Altitude Operating or Nonoperating TANDON CORPORATION CHATSWORTH 10 c to 46 C 50 F to 1159 409 to 719c 40 F to 160 F 20 to 80 percent 5 to 95 percent 500 feet below sea level 50 000 feet above 152 4 meters to 15 240 meters sea level CALIFORNIA 91311 179DDD 001 REV A SECTION 3 OPERATION INTRODUCTION This section con
22. 7 BLU RIZ NO 5V 39 GERN NsEL 5 ACTIVITY NMOTOR ON Wie SP N TIMER EDC 041 81 CONTROL RT 2 2K REVISIONS DESCRIPTION Seer 1 pe em D JI MOTOR RED 2 MOTOR RET BLU nee DATE mmm he a set E Tandon EMEN eret un ENGR fy fr Wx 1 MODEL TM 50 A PROJ tNGR 7 4 he CONTROL MOTOR SCHEMATIC MATL SIZE Koo IDENT NOJ DWG wees C 210439 J SCALE NONE DO NOT SCALE DWG BREAK ALL SHARP CORNERS APPROX 0 EV 5V STEPPER MOTOR edd CONTROL ETK 1 1 D 4 I J4 7 NOIRECTION WHT 3 STEP IN 15 998 94 Te STEP aah 9 NSTEPEN ORN 5V 5V 1 D 4 Dips 7909 304 R19 330 REVISIONS 10 3 3 7 T5V PD e 75724 T i 2 D 75464 45V a B 2 5 YEL pomo 7 uw BRN bg D E ORN BLK NOTE COLORS REFER RED TO MOTOR R23 mW WIRING 2 RED U2 UDN 12V 7404 cus 6 02 VERSION ONLY SINGLE PHASE STEP IN THE INFORMATION CONTAINED HEREON 5 THE PRO PERTY 04 TANDON CORPORATION NO PORTION OF THIS DATA SHALL BE AECEASED DISCLOSED USED OF Tandon ORN BAN TWO PHASES
23. 7 Wo 6 19 1 5 13 Track 0 OCOD q s e s wo s s or 5 18 5 14 Upper Arm and Compliance Spring s e s s 5 2 6 1 Control and Data Circuit Board o 6 4 6 2 Servo Circuit Board x s s oe ROG Xo o gt EL IET 6 4 6 3 Diskette Lever Assembly 6 4 6 4 Power Input Plug and Bracket e e e e o 6 5 6 5 Stepper Band a s s s s s 4 6 10 6 6 6 11 6 7 6 8 6 9 iv TABLES Paye Title Number Electrical and Operational Specifications 2 3 Reliability Specifications s s s e e 2 4 Environmental Specifications s e 2 5 Drive Interface Lines and Pin Assignments o 3 3 D C Power Connector Pin Assignments 3 8 SECTION 1 GENERAL DESCRIPTION INTRODUCTION This document provides required information in order to evaluate and incorporate Tandon s disk drive into a system Tandon Corporation s Model Number TM50 1 and 50 2 5 1 4 inch flexible drives are compact low profile drives that may be installed in only one half the space normally required They are compact data storage devices that use an ANSI compatible industry standard 5 1 4 inch diskette Model Number TM50 1 and TM50 2 drives each 48 tracks per inch The TM50 2 is a double sided recording device Both drives are capable of reading and writing in single density format on a diskette using a proprietry read write head patented
24. 84 001 Head Carriage Assembly SSR 210446 001 Head Carriaye Assembly DSR 210380 001 Index Sensor Assembly 210534 001 Stepper Assembly 211004 001 Stepper Assembly Fast Seek 210334 Drive Belt 210437 002 Motor Control PCBA 210437 003 Motor Control PCBA Fast Seek 210399 Drive Hub Assembly READ WRITE CONTROL BOARD E DRIVE MOTOR ASSY F UPPER PLATE ASSY D TRACK OO SENSOR ASSY WRITE PROTECT SWITCH ASSY c m w DISKETTE LEVER ASSY ASSY A FRONT BEZEL BANO ASSY H INDEX SENSOR ASSY J HEAD CARRIAGE ASSY 2 MOTOR CONTROL BOARD DRIVE BELT 1 STEPPER MOTOR ASSY x APPENDIX B CIRCUIT BOARD SCHEMATICS AND DRAWINGS This appendix contains a listing of the current circuit board schematics and circuit board drawings for the TM50 1 and TM50 2 drives Drawing Number Titie Page Number 210441 Revision J Read write Logic Circuit Board Schematic 1 2 B 3 B 4 210439 Revision H Motor Control Circuit Board Schematic B 5 B 6 B 7 SHIELD REVISIONS DESCRIPTION SEE SHT YEL RWI RED ERASE BLK RWG RED ERASE SHIELD D 75461 NERASE 4 B 1 2 82 3 c2 3 88 4 5 R32 sec 629 HI ie A 1570214 13 2 09 5 014 0 74221 7474 M no 4
25. A D N WRITE ENABLE N WRITE ERAS N WRITE PROTECT ORIVE SELECT ERASE DELAY CURRENT LOGIC SOURCE READ DISABLE N INTERNAL WRIT BUSY FIGURE 4 7 WRITE DATA CIRCUIT BLOCK DIAGRAM 4 10 NOTES 1 t O 250 MILLISECONDS AFTER DRIVE MOTOR STARTS OR 20 MILLISECONOS AFTER LAST STEP PULSE WHICHEVER 13 THE LATEST TIME 2 UNSYNCHRONIZED 3 8 5 MILLIAMPERES TO PEAK 4 4MICROSECONDS MINIMUM 8 MICROSECONDS MAXIMUM l end WRITE ENABLE e 390 MICROSECONDS gt MICRO E TRIM ERASE INTERNAL WRITE BUSY t N WRITE DATA dE c NOTE 27 i i 1 WRITE 1 i WAVEFORM GENERATOR 11 ae WRITE CURRENT a E La i anes dn ph el ef a s ea bas een FIGURE 4 8 WRITE OPERATION TIMING DIAGRAM 4 11 When there 15 pre erase delay 390 microsecond time out the erase current source is turned on The clocking of the waveform generator during write operation provides a trigger to the post erase delay one shot and does not allow it to time out until all data is written N Internal Write Busy is active until the
26. ART NUMBER VALUE d USAGE OF COMPONENTS Tet OUT Dx PRO SIGNATURES DATE APRECTED BY VERSION NUMBER SEE TABLE T TES DATA BERELESSED DURCLOSED USED OM Tandon ust iw of wan OR ESAE 2 Dun SPEEN WATTEN gt FOR 2 tS vey 4 ALL DOES ARE 444 NEL ys TE RTT TM SO ARE 20 Kee cok 2 1 Resistors SCHEMATIC 1 ALL RESISTORS ARE IN OHMS 4 5 FINISH MATL SIZE CODE IDENT NOTOWG NO REV NOTES UNLESS OTHERWISE SPECIFIEO 2 10 439 H BE KONE wororscneone ae ac BREAK ALL SHARP CORNERS APPROX 010 4 3 2 HI 10 19 08 11 3 SPINDLE MOTOR CONTROL 2 D 4 C 3 8 3 DESCRIPTION SEE 1 5V lt JI MOTOR RED 2 RI IK 9 5 GRY TACH 3 7 1 MOTOR RET BLU 3 L 2917 vet 12 8 IM Hu DISKETTE ENABLE SWITCH 7 GRN NSEL INFORMATION 15 THE PRO Roe ene Tandon FACTURING WITHOUT SPECIFIC ww YTEN PERMISSION 2 4 E Lp ACTIVITY PA 7 CX LED IP NMOTOR ON DIMENSIONS ARE IN INCHES TOLE
27. Activity Inaicator d ete 1 2 UGE qe ZELUS AD us 1 2 1 4 Functional Description s e s s e e s see s 1 2 1 5 Physical Description s e so wp X 1 3 SECTION 2 PRODUCT SPECIFICATIONS Introd uctLOnn xu wonder St Toe Tes Bee Gece 2 1 2 1 Mechanical Specifications s e a a e s s 2 1 2 2 Electrical and Operational Specifications 2 1 2 3 Reliability 5 1 1 1 5 2 1 2 4 Environmental 5 1 1 1 5 2 1 3 OPERATION introduction xe Ue 3 321 3 1 Unpacking The Drive e 3 1 3 2 Preinstallatlon Checkout e s s e s e e s s o oo a 3 3 Mounting The Drive a e s e s s e e s s VK CAO eo 3 2 Dust COVER s e o e s RI de Rd 3 2 4 L4 wo Xe e 3 2 3 4 Interface Connections 4 tec e e ce e s saes 3 3 Input Control Lines Co le alte lee IR e 3 4 Output Control Lines ow 3 6 Typical Interface Characteristics 3 7 3 5 POWOL 4 3 3 6 Drive Address and Option Patching e e 3 8 DSO Through DS3 Jumpers e e s 3 8 3 8 MX Jumper Section Number SECTION 4
28. C or equivalent or a software routine capable of stepping the drive to any track selecting the upper or lower head and writing a lF all zeros in or 2F all ones in FM pattern 3 A power Supply 4 certified alignment diskette Dysan Model 224 2A or equivalent 5 A certified output diskette write protected Dysan Model 104 2D with tab or equivalent 6 A certified output diskette nonwrite protected Dysan Model 104 2D or equivalent 7 Associated power and interface cables 8 A number 1 Phillips screwdriver 9 Jeweler Screwdriver speed adjust 10 Spring inserter remover 11 A flat blade screwdriver 3 l6 inch tip Test equipment must be calibration This may be verified by observing the calibration due date on the calibration sticker affixed to the equipment 5 3 POWER DRIVE SELECT CHECK The drive select check verifies the activity L D can be illuminated and power is supplied to the drive If the check fails measure the power supply voltages to ensure they are correct l Turn off power to the drive 2 Connect the interface cable that goes from the exerciser to the drive 3 Apply power to the drive 4 Verify power supply voltages are within tolerances 5 Ensure a drive select jumper is in place 6 Select the drive 7 Verify the front panel L E D is illuminated 8 Deselect the drive 9 Ensure the front panel L E D extinguishes 5 4 WRITE PROTECT SWITCH CHECK AND ADJU
29. D WRITE BOARD SCHEMATIC DOUBLE SIDED SIZE CODE IDENT NOJOWG NO REV 6 oaa oe 4 UNLESS OTHERWISE SPECIFIED ALL SHARP CORNERS APPROX 010 5V 4 pf 55 2 5 NWRT DATA 45v RPG IK 2 NWRT 2 C 3 NOTES UNLESS OTHERWISE SPECIFIED 4 5V R53 13 3K 17 41 5 gt Q 7406 3 gt gt Q 7406 2 1 Ix pepe A e Semat ane La Ful lo Boe REV DESCRIPTION pate ex 12VS 1205 SHT 1 2 5 226 WAH 2 us 10 et 360 750 MPa2207 CRIB 6345835 64 2 IK RP3 IN5234B 2750 5 750 REO a J6 7 3 D 4 1 ET jez 3 c 4 8 2K 8 2 CATHODE 5 3 Cc 4 768 17 RPS RPS 3 Ua 3146 4 7 5 RIZ IN 52 308 270 NWRT mi 12 3 QW7 7400 5 R34 2B 7K 17 NWRT o 2 c 3 w2 4 NERASE 32 w3 3 B 4 5 p 7590 W3 TUNNEL ERASE 13 W2 STRADDLE ERASE a v 16 MOMMA TION CONT AIMED 15 THE PRO 74125 Tum CIE om 2 y Tar FOR USE PROCUMEMENT OM Ie 7777 pp andon NINTWRT BSY nee Lee ANH CORPORATION 3 8 1
30. Differentially A plus B B inverted Time Base 50 microseconds per division External Trigger Test Point 12 negative edge NOTE TOLERANCE IS 200 100 MICROSECONDS I p ru NE ELE EERE TOT ZOOS EE GE PP OF RTE EEA URS E plete ULME SCALE 50 MICROSECONDS PER DIVISION FIGURE 5 8 INDEX TO DATA PULSE Adjust amplitude for at least two divisions on the oscilloscope Apply power to the drive Select the drive with the control logic Check the speed of the drive s motor Insert an alignment diskette 5 11 11 12 13 14 INDEX ASSEMBLY BELOW SERVO CIRCUIT BOARD INDEX SENSORS RETAINING SCAEW Seek the carriage to Track 1 Select Head 0 Read the trigger point to the start of the first data pulse width Figure 5 8 For double sided drives if Head 0 the lower head meets the tolerance check the upper head NOTE HEAD 1 SHOULD MEET THE SAME TOLERANCE If either head does not meet the tolerance adjust the index sensor Recheck both indexes after they are adjusted When both index measurements on a double sided drive or the one index measurement on a single sided drive meet the tolerance check the index on Track 34 For double sided drives check Heads 0 and 1 NOTE IF ANY INDEX MEASUREMENT DOES NOT MEET THE TOLERANCE THE INDEX SENSOR MUST BE ADJUSTED FIGURE 5 9 INDEX SENSOR S RETA
31. EL Tandon CORPORATION MODEL 50 A i READ WRITE BOARD SCHEMATIC TRN DOUBLE SIDED FINISH MATL SIZE OWG REV pur p serere 7 8 2 1 REVISIONS DESCRIPTION SEE SHT NWRTPROT 447 WRITE PROTECT 2 NTRZERO SWITCH 2820 2 A 4 7414 NC BLU NSTEPEN STEP BRN NDIRECTION WHT YELLOW YEL SEL HI sex 3 B 1 jui y 7486 HI 3 A 4 5V 9 5 NWKRTGATE R17 JIO N INUSE 10 IK N MOTOR ON N MOTOR ON VIO SEL GRN NSTEP DIR an STEPOUT Tandon NDS CORPORATION NDS ae MODEL 50 m READ WRITE BOARD NDS SCHEMATIC DOUBLE SIDED FINISH MATL SIZE CODE DENT NOjJ DWG NO REV NOTES UNLESS OTHERWISE SPECIFIED ee p 710441 EDC Da1 8 67 SHIELD RWI CT RWI RED ERASE BLU bis 2 Rw d RED ERASED 4 U3 1 4 C 1 7 NOTES UNLESS OTHERWISE SPECIFIED REVISIONS DESCRIPTION RS KIT eve ce 5844 Le NWR ejes THE WT ORLATION 18 PRO PERTY OF CORPORATION MO PORTION OF E OCT P Tandon SEES EG NEN CORPORATION ae MODEL _ 50 REA
32. ERANCE ON ALL DIMENSIONS 15 0 020 INCH UNLESS OTHERWISE SPECIFIED 3 WEIGHT IS APPROXIMATELY 3 POUNDS DISK DRIVE OUTLINE DRAWING TANDON CORPORATION CHATSWORTH CALIFORNIA 91311 179000 001 REV TABLE 2 1 ELECTRICAL AND OPERATIONAL SPECIFICATIONS Media Media Lite for reference only Tracks Per Inch Tracks Per Drive TM50 1 TM50 2 Track Spacing Head Life Disk Rotational Speed Average Rotational Latency Instantaneous Speed Variation ISV Motor Start Time Seek Time track to track Fast Step Motor Optional Head Settling Time Fast Step Motor Optional Average Track Access Time including head settling time Fast Step Motor Optional Typical Recording Modes Data Transfer Rate TANDON CORPORATION CHATSWORTH CALIFORNIA 91311 ANSI compatible 5 1 4 inch diskette 4 x 106 passes per track 48 TPI both drives 40 Tracks 80 Tracks 0 529 millimeters 20 8 milinches 20 000 media contact hours 300 RPM 1 5 percent 100 milliseconds 3 percent One second maximum 20 milliseconds 6 milliseconds 20 milliseconds 15 milliseconds 287 milliseconds 95 milliseconds FM MFM MMFM 250 000 bits per second double density 179DDD 001 REV A TABLE 2 1 CONTINUED ELECTRICAL AND OPERATIONAL SPECIFICATIONS Flux Reversals Per Inch FRPI inside track Both models Side 0 5 535 FRPI TM50 2 Side 1 5 877 FRPI Unformatted Recording Capacity TM50 1 250 kilobytes per disk TM50
33. Head 0 6 Measure the amplitude of the signal by positioning the deepest dip in the signal on the center vertical graticule 7 Release the front latch and remove the diskette 8 Reinsert the diskette and close the front latch 9 Repeat Steps 7 and 8 until the deepest dip in the waveform is produced 10 Measure the amplitude of the deepest dip 11 Divide this measurement by the measurement Step 6 and multiply it by 100 This result should be above 85 percent 12 The signal amplitude should not decrease below 85 percent of the average amplitude at any point on the track 5 13 COMPLIANCE CHECK AND ADJUSTMENT SINGLE SIDED DRIVES Compliance is the maximized output of the head when the pressure of the felt pad is centered over the read write gap For double sided drives a compliance check and adjustment must be made at the factory Compliance Check 1 Set up the oscilloscope Channel Test Point 4 Channel B Test Point 5 Vertical Amplitude 100 millivolts per division Ground Test Point 8 or 14 Read Differentially and inverted Time Base 10 microseconds per division External Trigger Test Point 12 positive edge 2 Apply power to the drive 3 Select the drive 4 Insert a nonwrite protected diskette 5 Write pattern on Track 34 6 Observe the output waveform voltage 7 With a gram gauge carefully apply fifteen grams pressure to the upper arm NOTE FIFTEEN GRAMS IS ABOUT THE WEIGH
34. INING SCREW AND ADJUSTMENT 5 12 15 Recheck all indexes after each adjustment Index Sensor Adjustment 1 From the bottom of the chassis loosen the index sensor s retaining screw counterclockwise one quarter turn Figure 5 9 through the access hole in the Servo circuit board 2 Adjust the index sensor with a flat blade screwdriver until the data pulse begins 200 microseconds 100 microseconds from the trigger point through the access hole in the servo circuit board 3 Tighten the index sensor s retaining screw 4 Recheck the index to data pulse 5 8 AZIMUTH CHECK Azimuth checks the read write head s relative angle to the center line of the diskette The Dysan 224 2D alignment diskette has three azimuth bursts the first one having acceptable limits of 12 minutes the second one 15 minutes and the third one 18 minutes The third burst of 18 minutes should be used for the check The head s azimuth is not adjustable If the head s fail the azimuth check replace the head carriage assembly 1 Set up the oscilloscope Channel A Test Point 4 Channel B Test Point 5 Ground Test Point 8 or 14 Read Differentially A plus B B inverted Time Base 0 5 millisecond per division External Trigger Test Point 12 positive edge Adjust the amplitude for at least four divisions on the oscilloscope 2 Seek to Track 34 3 Select Head 0 and observe the third pulse burst on the oscilloscope 4 Verify the head azimuth
35. OEM OPERATING AND SERVICE MANUAL TM50 1 AND TM50 2 THINLINE M 5 1 4 INCH FLEXIBLE DISK DRIVES 48 TRACKS PER INCH TANDON CORPORATION 20320 PRAIRIE STREET CHATSWORTH CALIFORNIA 91311 COPYRIGHT 1983 TANDON CORPORATION NOTICE This document and the information contained herein copyright by Tandon Corporation and may not be duplicated or reproduced in whole in part without the prior written approval of Tandon Corporation This document is intended to provide the user with detailed information adequate for the efficient installation operation and service of the equipment involved However while every effort has been made to keep the information contained herein current and accurate as of the date of publication no guarantee 15 given or implied as to its accuracy CONTENTS Section Page Number Title Number SECTION 1 GENERAL DESCRIPTION v i i 1 1 Scope Of The Documenb m s e s s e s e soseo l 1 1 2 Purpose Of The Drive Ao es es esso 1 1 143 Major Features i l Write Protect xx Daisy Chain Capability Ss ies Wee an fad SE a ee 1 2 Internal Trim Erase a 1 2 Industry Standard Interface Compatibility 1 2 Track 0 Sensor Lu Lk se 1 2 SENSOP So 4 at 1 2
36. P 15 ENCOUNTERED KEEP THE DISKETTE DISKETTES SHOULD HANDLE WITH CARE AWAY FROM BE STORED AT BENDING AND FOLD NETIC FIELDS 10 C 0 52 ING MAY DAMAGE 50 F to 125 F DISKETTE FIGURE 3 6 DISKETTE CARE AND HANDLING 1 Return the diskette to the protective jacket when not in use 2 Avoid exposing the diskette to any magnetizing force in excess of 50 oersted Note The 50 oersted level magnetizing force is reached at a distance of approximately three inches from a typical source g motors generators or transformers 3 avoid warping do not store the diskette in direct sunlight 4 Do not use a lead pencil or a ballpoint pen to write on the label Use a felt tipped pen and mark lightly on the label 3 14 SECTION 4 THEORY OF OPERATION INTRODUCTION This section contains a description on the theory of operation of the drive The discussion begins with a general summary of magnetic data recording followed by a description of each major function of the drive Circuit block diagrams and schematics are located in the appendices They are useful to show the interconnections between the electronic circuits and the mechanical components 4 1 DATA RECORDING Digital information is represented by a sequence of bits either 0 or l Small areas of the medium in which such binary information is Stored for example the iron oxide coating of a magnetic disk must be put in one state or the other
37. RANCES CORPORATION __ Fo Moy lis 10 74 2 oh a fum 2 x PROJ ENGA ic x MODEL TM 50 MOTOR CONTROL eee un SCHEMATIC aaa FINISH MATL SIZE T 210439 REV NONE eoworsceows SHEET 2 o g 4 42 2297 BREAK ALL SHARP CORNERS APPROX STEPPER MOTOR CONTROL 44 NDIRECTION 1 m HI STEP iN 9 D BR 7404 NSTEPEN ORN U8 7422 DESCRIPTION SEE SHEET 1 NOTE COLORS REFER TO MOTOR WIRING 002 VERSION ONLY TWO PHASES cw ecw STEP OUT STEP WW YEL BLK YEL BRN ORN BLK ORN BRN ORN BRN YEL BRN NOTES UNLESS OTHERWISE SPECIFIED 0 0 SINGLE PHASE STEP OUT STEP IN BRN ORN BLK HE INEGRMATION CONTAIMED HEREON 15 THE PRO PACTUMING wrTHOUT SPECIFIC WATTEN PERMISSION FAO TANDON CORPORATION DIMENSIONS ARE IN INCHES TOLERANCES ANGULAR n BREAK ALi CORNERS APPROX 010 FINISH SIGNATURES DATE ENGR Tandon CORPORATION MODEL TM 50 MOTOR CONTROL SCHEMATIC Est NONE Rez 150 22 5 CHARACTET2 ISTIC 76601 00 PED 621 RIB OMIT Se an L C TABLE 7406 7474 74191 15464 SPARE GATES 9 9 2 93 UA 5 6 97 LAST USED
38. S INDEX 4 4 MILLISECONDS Bi 500 NANOSECONDS MAXIMUM TRACK 500 NANOSECONDS WRITE aaa SIDE SELECT 100 NANOSECONDS 20MILLISECONDS I MINIMUM 100 NANOSECONDS 200 NANOSECONDS MINIMUM MINIMUM 100 NANOSECONDS MINIMUM 40MILLISECONDS MAXIMUM WRITE GATE 250 MILLISECONDS i MINIMUM 900 MICROSECONDS 2390 MICROSECONDS ERASE GATE TUNNEL ERASE 200 NANOSECONDS ETATE ET zr MINIM MICROSECONDS WRITE DATA MAXIMUM r pee 19O MICROSECONDS 4 8 MICROSECONDS Ha MICROSECONDS READ DATA Mti ec pao E 250 MILLISECONDS 1 MICROSECOND 250 MINIMUM NANOSECONDS MICROSECONDS NOTES FOR REFERENCE ONLY 6 MILLISECONDS FOR FAST STEP MOTOR OPTIONAL 21 MILLISECONDS FOR FAST STEP MOTOR OPTIONAL FIGURE 3 2 CONTROL AND DATA TIMING REQUIREMENTS 3 9 zie pu pun 3 ERE 2 i ry gt C 11 MTS 91 ee 757 72 019 um USED 16 2 DSO 15 3 DSi 14 4 052 13 5 053 12 6 MX 11 7 NOT USED 10 8 MTR SEL 9 FIGURE 3 3 LOGIC BOARD WITH PROGRAMMABLE SHUNTS AND OPTION PATCHING LOCATIONS 3 10 Motor Select Jumper The Motor Select jumper MTR SEL should be connected when the spindle motor is to be t
39. STMENT The write protect switch check and adjustment establishes the correct operation of the write protect switch i e the write electronics are disabled when a write protected diskette is used Write Protect Switch Check 1 Connect the drive to an exerciser or computer with a direct monitor of the write protect output J8 Pin 28 or with no power to the drive disconnect Plug 1l and check the continuity with an ohmeter 2 With a nonwrite protected diskette inserted verify there is continuity between the two wires of Plug 11 or there is a nonwrite protected output to the exerciser i e a high at J8 Pin 28 3 With a write protected diskette inserted verify there is no continuity between the two wires of Plug 11 or that there is a write protect true output to the controller or exerciser i a low at 08 Pin 28 NOTE A DEFECTIVE CIRCUIT BOARD CAN BE RESPONSIBLE FOR A WRITE PROTECT PROBLEM TEST POINT 2 SHOULD BE LOW FOR A WRITE PROTECTED DISKETTE HIGH FOR A NONWRITE PROTECTED DISKETTE Write Protect Switch Adjustment 1 Loosen the screws holding it to the bracket the side nearest to the front of the drive Figure 5 2 2 Move the switch up or down as required and recheck it 5 5 DRIVE MOTOR SPEED CHECK AND ADJUSTMENT The long term drive motor s speed adjustment ensures the speed is within the specified tolerance The motor speed tolerance is 300 RPM 1 5 percent Drive Motor Check 1 Verify pow
40. T OF A QUARTER 8 If the output shown on the oscilloscope increases by more than ten percent adjust the compliance Compliance Adjustment Compliance is adjusted by usiny the same procedure used in the compliance check In addition 1 The spring tension for the pad arm has three positions for the spring end in the lower portion on the head carriage assembly see Figure 5 14 2 While monitoring the oscilloscope change the spring tension position If output amplitude is not affected by different positions of the spring replace it 3 the pad is worn replace it FELT PAD SNAPS INTO ARM ASSEMBLY 1 COMPLIANCE SPRING COMPLIANCE SPRING HAS THREE TENSION POSITIONS ANGLE OF 3107 DETERMINES SPRING TENSION FIGURE 5 14 UPPER ARM AND COMPLIANCE SPRING SECTION 6 REMOVAL AND INSTALLATION Removal and installation instructions are included in this section 1 Control and Data Circuit Board 2 Servo Circuit Board 3 Chassis Shield 4 Diskette Lever Assembly 5 Front Panel 6 Power Input Plug and Bracket 7 Write Protect Switch 8 Write Protect Sensor 9 Stepper Band 10 Stepper Motor 11 Upper Plate Assembly 12 Track 0 Sensor and Stop Block 13 Head Module 14 Drive Belt 15 Drive Motor CONTROL Removal 1 2 3 AND DATA CIRCUIT BOARD Disconnect all cable pluys from the circuit board located on top of the drive Remove two Number 1 Phillips screws at the rear of th
41. W7 B 7400 5V 45N L R33 R34 13 3K 17 7 NN e a W2 5V 4 37875 1 cae 6 3 84 S Ue p ay 7400 ik alt ce 15 W3 TUNNEL ERASE 2 5 2 13 2 STRADDLE ERASE 74 oare E mos zx E Tandon NWR q ab P NINTWRT BSY CORPORATION 2 3 3 8 1 7 mM RD MODEL 50 READ WRITE BOARD SCHEMATIC MATL Xx ANGULAR 1 im BREAK ALL SHARP CORNERS APPROX 0 0 DOUBLE SIDED oc ner oru NOTES UNLESS OTHERWISE SPECIFIED DESCRIPTION DATE APPR REVISED PER 13044 Mer I REVISED PER EO 13795 2 pz ABLE 122 REVISED PER EO 13206 Bae REVISED EO 15586 1500 57 l CHARACTER ISNC 47500 oo doom eI C21 cie a D STANDARD OMIT 4 3K 1 OMIT WEL Use SK I PROTEC use use TABLE U0N57I2M SPARE GATES 93 94 LM 23I1 7406 7404 7474 95 96 97 74191 74221 15464 LM5S5 m E LAST USEO PIN LIST CONN OF PINS SPINDLE MOTOR POWER STEPPER B CONTROL DISKETTE LOADED com P
42. X 45v 48 l 3 cio 2 uia 8 N INDEX 001 7438 8 m i B NWRI PROT 7438 JU 45V 9 LO WRITE PROTECT WRITE PROTECT 10 pH ze NTRZERO SWITCH 20k TP2 2820 gt 7438 74 504 2 4 414 4 5 ORN Q 5 1 succ aeu Rz 2 74 00 744504 3 STEP NDIRECTION WHT TR OO 2 YELLOW SENSOR NEL S L H 45V Vop set 3 1 7 3 2 8 gt 5 7486 3 H1 3 A 4 5V 5 NWRTGATE 55 TP3 RIT N INUSE go 4 7K 4 10 E IK 5 MOT 7 yy MOTOR 6 ON 7546 NIO 5V Te 5 NSEL 6 lt 150 2 150 9 504 GRN DIR 2 2 MEE 5 STEPOUT TORY OF TANDON COMPORATION PORTION OF SIGNATURES Tandon 15 2 UNO E NETTES ramon X NDS FROM TANOON CORPORATION lt 7 CORPORATION 3 NDS 1 13 ARE INCHES MODEL TM 50 s READ WRITE BOARD A 5 BREAK ALL SHARP CORNERS SCHEMATIC NDS 3 72 5 DOUBLE SIDED SIZE CODE IDENT NO DwG NO REV zoa PETZ 2 NOTES UNLESS OTHERWISE SPECIFIED
43. by Tandon The drives have a double density capability when a Modified Frequency Modulated MFM or other appropriate recording technique is used Encoding and decoding of the data is done by the user s controller Dd SCOPE OF THE DOCUMENT This document contains the major features physical and functional specifications mounting and power requirements the interface and typical timing characteristics of the TM50 1 and TM50 2 drives In addition there is a theory of operation checks and adjustment procedures replacement procedures assembly drawings and schematics 154 PURPOSE OF THE DRIVE 50 1 and TM50 2 drives are rotating disk memories designed for random access data entry storage and retrieval applications Typical applications include intelligent terminal controllers microcomputers word processing systems data communication systems error logging program loading and point of sale terminals 1 253 MAJOR FEATURES Write Protect When a write protected diskette is inserted into the drive the write electronics are disabled l 1 Daisy Chain Capability The drive provides the address selection and gating functions necessary to daisy chain a maximum of four units at the user s option The last drive of the daisy chain terminates the interface The terminations are accomplished by a resistor array plugged into a DIP socket Internal Trim Erase The drive provides the control signals necessary for proper
44. cw ecw STEP OUT STEP IN STEP OUT DUPLICATED FOR USE PROCUREMENT MANU FACTORING WITHOUT SPECIFIC WRITE PERISSION TANDON CORPORA TION YEL CORPORATION DIMENSIONS ARE IN INCHES TOLERANCES ORN BLK ENGR ANGULAR 1 aem MODEL TM 5O YEL BLK MOTOR CONTROL SCHEMATIC x J BREAK ALi SHARP CORNERS NOTES UNLESS OTHERWISE SPECIFIED EOC 041 4 8Y APPROX 00 uem FINISH MATL SIZE CODE IDENT NO DWG NO REV C 210439 F SCALE NONE DO NOT SCALE DWG 2 1 D B 6 5 4 3 2 A I C 7ABLE DATE DESCRIPTION PRELIMINARY RELEASE PRE PROD Ri cASE Pek EO 171 x PRE PROD RELEASE PER EO 12810 4 4 REV PER EO 72960 ots REV PER EO 2970 REV PER 3048 REV PER EQ 13288 PIN DIP COLORS REFER TO HARNESS WIRING ALL DIODES ARE 1 4446 CAPACITORS ARE IN 10 ALL 19 RESISTORS ARE 8 W ALL RESISTORS ARE IN OHMS IAW 5 ALL ODD NUMBERED PINS ARE CONNECTED 70 GROUND NOTES UNLESS OTHERWISE SPECIFIED EDCO4 82 4 3 B c D E F H REV M REV PER co 13254 REV PER 13301 40550 2 INCORP 90387 INCORP EO 903698 2 2843 2 7 APPLICABLE P C B REV LEVEL APPLICABLE ASSY REV LEV
45. d assembly several times on its rails to ensure it does not bind Replace the Track 0 sensor Replace Replace Replace Replace the stepper band the the the power input plug chassis shielding data and control circuit board DRIVE BELT Removal 1 the control and data circuit board 2 Remove the chassis shield 3 Remove the diskette lever assembly 4 Remove the front panel 5 Remove the servo circuit board 6 Remove the bottom index sensor 7 Remove the upper plate assembly 8 Unloop the drive belt from the drive motor pulley 9 Lift out the drive belt through the slot in the chassis Installation 1 Twist the belt so the shiny side is inward 2 Push the new belt through the slot in the chassis looping the belt around the spindle pulley 3 While turning the spindle pulley loop the other end of the belt around the drive motor pulley 4 Ensure the spindle pulley drive belt and drive motor rotate freely 5 Replace the upper plate assembly 6 Replace the bottom index sensor 7 Replace the servo circuit board 8 Replace the front panel 9 Replace the diskette lever assembly 10 Replace the chassis shield ll Replace the control and data circuit board 6 17 DRIVE MOTOR Removal On the servo circuit board remove cable Plug Pl Cut the tie wrap at the front of the stepper motor Figure 6 9 Cut the tie wraps by the drive motor on the bottom of the drive one in the co
46. d horizontally the logic circuit board side of the drive must be the top side Tapped mounting holes are provided on each side and the bottom of the drive for attachment to user supplied mounting brackets Figure 2 1 When installed in either plane horizontal or vertical only two mounting screws are required to securely hold the drive in place Two drives may be mounted a single full size drive enclosure 3 25 inches high A two hole mounting scheme per drive is recommended for mounting in a two drive configuration Any mounting scheme in which the drive is part of the structural integrity of the enclosure is not permitted Mounting schemes should allow for adjustable brackets or incorporate resilient members to accommodate tolerances In addition it is recommended that mounting Schemes include no more than two mounting surfaces The drive is manufactured and tested with some critical internal alignments that must be maintained Hence it is important that mounting hardware not introduce significant stress on the chassis Dust Cover The design of enclosure should incorporate means to prevent contamination from loose items g dust lint and paper chad since the drive does not have a dust cover Cooling Heat dissipation from a single drive is normally 15 watts 51 BTU per hour under high load conditions When the drive is mounted so the components have access to a free flow of air normal convection cooling al
47. drive required to control the spindle are 1 Spindle Motor and Spindle Assembly 2 Spindle Motor Enable circuit 3 Spindle Motor Control circuit 4 Diskette Enable Switch Spindle Motor ana Spindle Assembly The Spindle Assembly is driven by a belt attached between two pulleys The drive motor pulley is turned by a D C motor with a built in integral tachometer The spindle pulley connects to a hub that rotates a clamped diskette Spindle Motor Enable Circuit The Motor On signal is derived from the host controller to the inter face connector via J8 Pin 16 This Signal is buffered and supplied to the servo circuit board which uses it to enable the motor current circuit of the spindle motor control via 210 Pin 6 UPPER HEAD TM50 2 T ONLY READ AMPLIFIER READ ONLY TEST AND SIDE SELECT me D LINEA ONE 36 CIRCUITS LOWER H TESTPOINT ZERO CROSSOVER TIME DOMAIN DETECTOR oer COMPARATOR FILTER TEST POINT gt TEST POINT 9 DIGITIZER DATA OUTPUT ORIVE SELECT FIGURE 4 9 READ CIRCUIT BLOCK DIAGRAM 4 13 Spindle Motor Control Circuit The Spindle Motor Enable signal is input via J4 Pin 6 of the motor control circuit board to gate the spindle motor current Figure 4 10 This current is controlled by an integrated regulator circuit when the spindle motor is enabled The potentiator provides an adjustable D voltage reference to the regulator circuit for spindle speed adjustment The tachometer s
48. e circuit board Lift off the drive Installation 1 2 Position the circuit board on top of the drive Secure the circuit board with the two previously saved screws Connect all cable plugs Figure 6 1 SERVO CIRCUIT BOARD Removal 1 2 Position drive with drive belt top disconnect all cable plugs from the circuit board Remove the Number 1 Phillips screw at the left front and the Number 1 Phillips screw going through the heat sink on the circuit board NOTE THIS IS LONGER THAN THE OTHER SCREW REMOVED When removing the circuit board do not break off the L E attached to the edge of it and do not stretch the drive belt NOTE IF THE WRITE PROTECT CIRCUIT IS A SENSOR ATTACHED TO THE CIRCUIT BOARD USE CARE WHEN REMOVING IT Installation l Position the circuit board with the L E D lined up to the retaining cavity on the front panel Insert the L E D and move the belt slightly to position the circuit board 6 2 CHASSIS Removal 1 2 34 Secure the circuit board using the short Number 1 Phillips Screw through the mounting hole at the front The longer Number 1 Phillips screw is used through the heat sink on the circuit board Connect all cable plugs Figure 6 2 SHIELD CONTROL AND DATA CIRCUIT BOARD Remove the control and data circuit board Remove the Number 1 Phillips screw s retaining shield NOTE HEAD CABLING IS AT THE FRONT OF THE DRIVE Lift the s
49. e data are 1 Read Write Head Assembly 2 Side Select circuits 3 Write Erase circuits 4 Read Data circuits Read Write Head Assembly The read write head s are glass bonded ferrite cores mounted a ceramic structure The lower head structure is mounted in a fixed position to plastic carriage The upper head is mounted to a gimballed flexure to conform to the diskette The head carriage assembly is attached to the chassis on guide rails It is positioned by a split band attached to the stepper motor Side Select Circuits The Side Select signal is derived from the host controller via the interface connector 98 Pin 32 This signal is buffered If the Signal is high at the interface Side 0 is selected by applying a voltage potential on the center tap of Head 0 and allows current to flow in the coils of Head 0 If the signal at the interface is low Side 1 is selected applying a voltage potential on the center tap of Head 1 allowing current to flow in the coils of Head 1 In the read mode potential of 5 volts D C is applied to the selected head diode matrix The write mode increases the voltage applied to the selected head diode matrix to 12 volts D C from the beginning of Write Enable until the end of Internal Write Busy Write Erase Circuits The write electronics consist of a write current source a write waveform generator an erase current source the trim erase control loyic and the side select logic
50. en the two Number 1 Phillips screws retaining the write protect switch actuating arm and screw retaining plate 5 Slide the assembly off of the chassis Installation 1 After positioning the write protect switch and actuating arm screw the retaining plate into the chassis slot 2 After ensuring the actuating arm is in the chassis slot tighten the two screws 3 Route cable plug Pll through the hole in the chassis toward the rear of the drive around the outside of the drive motor to the control and data circuit board 4 Replace the tie wrap 5 Replace the servo circuit board WRITE PROTECT SENSOR Removal 1 Fa Remove the servo circuit board NOTE ONE HALF OF THE SENSOR IS ATTACHED TO THE PHOTOTRANSISTOR At the top left hand front of the drive the write protect sensor s diode mounting block is retained by a Number 1 Phillips screw Remove the screw and cut the tie wraps as required to remove Plug Pll from the control and data Circuit board Remove the sensor s diode Installation 1 Replace the servo circuit board STEPPER Removal Align the mounting block with the sensor over the hole on the top left hand front of the drive and secure it with a Number 1 Phillips screw Route the cables and plug Pll into the connector on the control and data circuit board Wrap the cables as required BAND Remove the control and data circuit board Remove the chassis shield Remove the power i
51. er 12 volts D C 6 volt 5 volts D 29 VOLE 2 Apply power to the drive 5 4 NUT PLATE WRITE PROTECT SWITCHING FIGURE 5 2 WRITE PROTECT SWITCH ADJUSTMENT 3 Activate the drive motor 4 Insert a work diskette 5 Observe the speed disk on the spindle pulley under ambient flourescent lighting 6 Verify the 60 Hertz outer ring is stationary Drive Motor Adjustment 1 Adjust R15 located on the Servo circuit board until the speed disk is stationary Figures 5 3 and 5 4 5 6 RADIAL The Radial the proper location is servicing or if diskette interchange problems are suspectod TRACK ALIGNMENT CHECK AND ADJUSTMENT Track alignment procedure locates the read write head at radial distance on the hub center line ensuring the track accurate Figure 5 5 Adjustment is necessary only after 24 SPINOLE SPEED CONTROL FIGURE 5 3 LOCATION OF R15 SPEED CONTROL POTENTIOMETER INNER SARS ON TIMING 913 TIMING AING USED FOR 50 Hz FIGURE 5 4 BOTTOM VIEW OF DRIVE 5 6 HUB CENTER LINE 1 128 0 0005 TRACK 1 INDEX OATA TRACK 16 CATS EYE PATTERN TRACK 34 AZIMUTM FIGURE 5 5 HUB CENTER LINE AND TRACK LOCATION NOTE THE ALIGNMENT DISKETTE AND DRIVE MUST BE ALLOWED TO STABILIZE AT ROOM TEMPERATURE FOR ONE HOUR BEFORE CHECKS AND ADJUSTMENTS ARE PERFORMED Radial Track Alignment Check l Set up oscilloscope Channel A Test Point 4 Channel B
52. from the stepper motor to the side of the chassis 6 10 Insert stepper motor cable plug P3 into the servo circuit board Tie wrap the cables Replace the stepper band Replace the chassis shield Replace the control and data circuit board STEPPER 1 PHILLIPS RETAINING SCREWS BOTTOM OF DRIVE FIGURE 6 6 STEPPER MOTOR 6 11 UPPER PLATE ASSEMBLY The upper plate assembly includes the door switch the upper index sensor the cone lever assembly the diskette ejector the lift plate and the diskette lever assembly as well as the write protect sensor if applicable Removal 1 Remove the control and data circuit board 2 Remove the chassis shield 3 Remove the diskette lever assembly 4 Remove the front panel 5 Remove the servo circuit board 6 Remove the bottom index sensor 7 Cut the tie wraps on the cables for the door switch Plug 5 the index assembly Plug 12 and write protect Plug 11 if the sensor is mounted on the upper plate assembly Figure 6 7 NOTE ONE HALF OF THE INDEX ASSEMBLY IS ON THE BOTTOM OF THE DRIVE THE INDEX ASSEMBLY SHOULD BE ROUTED THROUGH A HOLE IN THE CHASSIS BEFORE REMOVING THE UPPER PLATE ASSEMBLY 8 Remove the spring from the lift plate 9 Remove three Number 1 Phillips screws from the upper plate assembly Two are at the front of the drive and one is on the drive motor side of the chassis CAUTION WHEN REMOVING THE UPPER
53. hield from the chassis Installation l 2 3 DISKETTE Removal 1 2 Position the head cables along the chassis to exit the slot of the shield at the front of the drive Position the shield securing it with a Number 1 Phillips screw through the mounting hole Replace the circuit board LEVER ASSEMBLY Using a flat blade screwdriver pry off the plastic door handle Figure 6 3 Remove the stud from the door shaft Installation 1 2 3 Replace the stud in the door shaft Position the door handle over the shaft and stud Press in until the stud is covered by the door handle T1 1713 Te 10 FIGURE 6 1 CONTROL AND DATA CIRCUIT BOARD MOUNTING SCREWS FIGURE 6 2 SERVO CIRCUIT BOARD FIGURE 6 3 DISKETTE LEVER ASSEMBLY 6 4 FRONT PANEL Removal 1 Remove the diskette lever assembly 2 The front panel is held in place by small plastic ridges To remove them from the bottom pull down and out To remove them from the top upper plate assembly pull up and out and slide them off of the door shaft Installation 1 Position the front panel over the door shaft and activity L E D and push it hard The front panel snaps onto the chassis and upper plate assembly POWER INPUT PLUG AND BRACKET Removal 1 Remove the control and data circuit board 2 Remove the chassis shield 3 Remove the Number 1 Phillips screw from the powe
54. ignal provides feedback from the motor via Pins 3 and 4 of Jl of the motor control circuit board to maintain a constant speed of 300 RPM This signal is 12 volts A C Diskette Enabled Switch Door Lever With power applied to the drive unit and the motor enable false inserting a diskette into the drive and closing the door lever turns on the motor for five seconds This feature ensures the proper clamping of the diskette to the spindle hub and the centering cone Motor control be accomplished by drive select with 1 installed ag Q E 50 MOTOR DIHIN SPINDLE SPEED CONTROL FIGURE 4 10 SERVO CIRCUIT BOARD 4 14 SECTION 5 MAINTENANCE CHECKS AND ADJUSTMENTS INTRODUCTION This section is for the use of the OEM Repair and Service Departments It contains the maintenance checks and adjustments used during the normal life of the drive The purpose of this section is to outline the steps necessary to verify the operation of the drive during troubleshooting or after replacing a part or assembly If a fault is suspected with a drive following the checks and adjustments in the order presented will help to isolate the problem area However if a specific check and adjustment is required the preceding checks do not necessarily need to be performed The values and tolerances stated in the checks and adjustments are typical values for working drives If the values measured are within tolerances or
55. is no greater than 18 minutes by comparing the third set of pulse burst to those in Figures 5 10 5 11 and 5 12 5 13 5 Select Head 1 and verify the head azimuth Figure 5 10 depicts an azimuth of exactly zero minutes This is tho optimum head azimuth alignment FIGURE 5 10 OPTIMUM HEAD AZIMUTH ALIGNMENT Figure 5 11 depicts azimuth of exactly minus 18 minutes This is the lower limit of allowable azimuth error T FIGURE 5 11 HEAD AZIMUTH ALIGNMENT OF ACCEPTABLE LOWER LIMITS Figure 5 12 depicts an alignment of exactly plus 18 minutes This is the upper limit of allowable azimuth error 5 9 _ FIGURE 5 12 HEAD AZIMUTH ALIGNMENT OF ACCEPTABLE UPPER LIMITS TRACK 0 SENSOR CHECK AND ADJUSTMENT The Track 0 sensor circuitry provides a signal identifying Track 0 to the logic electronics The electronics disable the step out function when Track 0 is reached addition a Track 0 signal is sent to the controller on Pin 26 of the interface Track 0 Sensor Check Set up the oscilloscope Channel A Test Point 4 Channel B Test Point 5 Ground Test Point 8 or 14 Read Differentially A plus inverted Time Base 20 milliseconds per division External Trigger Test Point 12 positive edge Vertical Display 0 1 volt per division Apply power to the drive Insert a certified alignment diskette into the drive Close the front latch Step the carriage
56. isk Drive To Controller Signal Index Sector Track 0 Write Protect Composite Read Data Connector Clamp input Controi Lines Drive Select Lines The Drive Select lines provide a means of selecting and deselecting a drive These four lines select one of the four drives attached to the controller When the signal logic level is true low the drive electronics are activated and the drive is conditioned to respond to Step or Read Write commands A Drive Select line must remain stable in the true state until a Step or Read Write command is completed When the signal line logic level is false high the input control lines and output status lines are disabled The drive address is determined by a select shunt on the logic circuit board Drive Select lines 0 through 3 provide a means of daisy chaining a maximum of tour drives to a controller Only one can be true low at time An undefined Operation results if two or more drives are assigned the same address or if two or more Drive Select lines are in the true low state simultaneously Motor On When this signal is true low the drive motor accelerates to its nominal speed of 300 RPM and stabilizes at this speed in less than one second When the signal line logic level goes false high the drive decelerates to a stop This signal is not gated with Drive Select Direction Select and Step Lines Two Lines When the drive is selected a true low pulse o
57. lectrical and mechanical components required to pertorm four major functions 1 Generate and interpret control signals 2 Position the read write head s to the desired track 3 Write and read data 4 Control the spindle The electrical and mechanical components of the drive are connected together via multiple pin connectors This allows the individual assemblies to be removed Figure 4 4 4 3 GENERATE AND INTERPRET CONTROL SIGNALS The components of the drive required to generate and interpret the control signal Ta Index Sensor 2 Write Protect Switch 3 Track 0 Sensor 4 Drive Select Index Sensor The Index signal is derived from an infrared L E D and photo transistor detector when the index sector hole in the diskette passes through the index sensor the light from the L E D is allowed to turn on the index detector producing a positive pulse on Jl2 Pin 4 Figure 4 5 This signal is shaped by an input buffer U9 and supplied co inverter IC 17 Then it is gated with Drive Select for an output control signal at the interface J8 Pin 8 TEST POINT 7 L MILLISECONDS AVERAGE 200 MILLISECONDS FIGURE 4 5 SOFT SECTORED INDEX PULSE Write Protect Switch The Write Protect signal is derived from a mechanical switch integrated into the drive the switch is deactivated causing a high signal on Jll Pin 5 Then it is buffered and inverted to disable the Write Enable signal is also gated with
58. lows operation within the specified temperature range When forced air is used air flow must be directed outward from the drive Do not intake air through the drive or eads and diskettes The use of forced air flow is recommended when two drives are mounted within a single enclosure 3 4 INTERFACE CONNECTIONS Interface connections tor the 50 1 and TM50 2 drives are made via a user supplied thirty four pin flat ribbon connector 3M Part Number 3463 0001 or AMP Part Number 583717 5 using contact Part Number 1 583616 1 for twisted pair its equivalent This connector mates directly with the circuit board connector at the rear of the drive The D C power connector has tour pins and is located at the rear of the drive The interface description of the connectors and the location of each one is contained in this section Interface lines are located in Table 3 1 C power connector pin assignments are located in Table 3 2 The signal wire harness should be of the flat ribbon or twisted pair 26 to 28 gauge conductor compatible with the connector to be used The recommended cable length is ten feet maximum TABLE 3 1 DRIVE INTERFACE LINES AND PIN ASSIGNMENTS Input Control Lines Controller To Disk Drive Ground i Signal Connector Clamp Spare Drive Select Drive Select Drive Select Drive Select Motor On Direction Select Step Composite Write Data Write Enable Side Select Output Control Lines D
59. media When single density FM type encoding technique is used in which data and clock form the combined Write Data signal it is recommended that the repetition of the high to low transitions while writing all zeros be equal to one half percent and the repetition of the high to low transitions when writing all ones be equal to the maximum data rate 250 kilohertz 0 1 percent Host controllers may implement write precompensation circuits that recognize worst case patterns and adjust the write data waveform Although a value cannot be specified for write precompensation Tandon suggests a value of 250 nanoseconds for systems using MFM double density recording format Write Enable When this signal is true low the write electronics are prepared for writing data and the read electronics are disabled This signal turns on write current in the selected read write head Data is written under the control of the Composite Write Data and Side Select input lines When the Write Enable line is false high all write electronics are disabled When a write protected diskette is installed in a drive the write electronics are disabled irrespective of the state of the Write Enable or Side Select lines Side Select TM50 2 The Side Select interface line defines which side of a two sided diskette is used for information transfer A false high level on this Line selects the read write head on side zero tne lower head of the drive
60. n in contact with the recording media until the front latch is opened The heads are positioned over the desired track by means of a four phase stepper motor band assembly and its associated electronics This positioner uses a one step rotation to cause a one track linear movement Data recovery electronics include a low level read amplifier differentiator zero crossover detector and digitizing circuits No data decoding capabilities are provided The drive has the following sensors 1 A Track 0 sensor detects when the head carriage assembly is positioned at Track 0 2 An index sensor is positioned to generate a digital signal when an index hole on the diskette is detected The index sensor distinguishes index and sector holes in a hard sectored diskette 3 write protect sensor disables the write electronics when a write protect tab is applied to the diskette 4 A motor control switch 1 5 PHYSICAL DESCRIPTION representative drive is shown in Figure 1 1 The drive can be mounted in a vertical or horizontal plane However the logic circuit board must be on the uppermost side when the drive is mounted horizontally The spindle is belt driven by a D motor with an integral tachometer The servo control circuit and tachometer control the speed of the spindle The read write head assembly is positioned by a split band positioner mounted to stepper motor The read write heads are glass bonded ferrite ceramic
61. n the Step line with a time duration greater than 200 nanoseconds initiates the access motion The direction of motion is determined by the logic State of the Direction Select line when a step pulse is issued The motion is toward the center of the disk if the Direction Select line is in the true low state The direction of motion is away from the center of the disk if the Direction Select line is in the false high state To ensure proper positioning the Direction Select line should be Stable at least 100 nanoseconds prior to issuing a corresponding step pulse and remain true low 100 nanoseconds after it The access motion is initiated on the trailing edge of the step pulse The time period between consecutive trailing edges of step pulses Shouid be at least 20 milliseconds The drive electronics ignore step pulses when one of three conditions exists l The write enable is true low 2 The direction select is false high and the head is positioned at Track 0 3 The drive is not selected Composite Write Data When the drive is selected this interface line provides the bit serial composite write data pulses that control the switching of the write current in the selected head The write electronics must be conditioned for writing by the Write Enable line For each high to low transition on the Composite Write Data line a flux change is produced at the write head gap This causes a flux chanye to be recorded on the
62. nce Adjustment REMOVAL AND INSTALLATION 6 a gt Control and Data Circuit Board Servo Circuit Board Chassis Shield Control a Diskette Lever Assembly Front Panel Power Input Plug and Write Protect Switch Write Protect Sensor Stepper Band Stepper Motor Upper Plate Assembly nd Data Circuit Bracket a Track 0 Sensor and Track Head Module REC Drive Belt Drive Motor Recommended Spare Parts and Major Assemblies Circuit Board Schematics iii and Drawings Page Number 5 6 5 7 5 10 5 10 5 11 5 13 5 413 5 15 5 15 5 16 5 16 5 17 5 19 5 20 5 20 5 21 mh T ILLUSTRATIONS FIGURES Figure Page Number Title Number 1 1 DISK Drive s snele suo Sp vet Sk 1 4 2 1 Disk Drive Outline Drawing s s e e eos 2 2 3 Electrical Interface Characteristics y x vo 3 7 3 2 Control and Data Timing Requirements 3 9 3 3 Logic Board With Programmable Shunts and Option Patching Locations vs SW e a s x us 3 10 Recording VAR 3 12 Write Protect Tab at ow ds 3 13 Diskette Care and Handling s v s 0 3 14 3 4 3 25 3 6 4 1 bilectromagneticoCOPFe s s Woo de
63. nput plug Loosen the Number 1 Phillips screw on the stepper motor shaft Figure 6 5 CAUTION WHILE HOLDING THE HEAD ASSEMBLY DURING REMOVAL OF THE STEPPER BAND TAKE CARE TO PROTECT THE UPPER HEAD ASSEMBLY Holding the head assembly toward the rear of the drive depress the spring tension plate at the rear of the head assembly toward the stepper shaft to the front of the drive The stepper band will detach from the clip portion of the tension plate CAUTION DO NOT BEND THE STEPPER BAND Remove the tension plate and the spring from the head assembly Remove the screw from the stepper motor shaft CAUTION DO NOT BEND THE STEPPER BAND Lift the stepper band from the stud at the front of the head assembly and from the stepper shaft 6 8 Installation 1 10 1l 12 13 Place the stepper band with its single part toward the ront of the head assembly Place a loop around the stepper shaft with its dual portion toward the rear of the drive Place the stepper band on the stud of the head assembly Rotate the stepper motor until the center hole in the stepper band and the hole in the shaft line up together Install the screw and washer into the stepper shaft but do not tighten the screw Install the spring and tension plate onto the head assembiy Holding the head assembly toward the rear of the drive depress the tension plate toward the front of the drive After setting the end of the stepper
64. on patching is determined by the programmable shunt located at 019 on the logic circuit board The DSO through DS3 jumpers determine the drive address The MX jumper is used only in single drive systems Drive address and option patching jumpers are located in Figure 3 3 The program shunt 15 AMP Part Number 435704 7 The shunt positions can be cut using AMP s tool Part Number 435705 shunt is in stalled socket At the user s option it can be removed replaced by a DIP switch DSO Through 53 Jumpers When daisy chaining two or more drives to a controller the Drive Select DS jumpers patch the drive select control signal to enable the logic of the proper drive Normally all the shunt jumpers would be cut except for the DS jumper that addresses each individual drive in the daisy chain The terminator pack 2F located the logic circuit board should be installed in the last drive of the daisy chain MX Jumper The Multiplex MX jumper is used only in single drive systems when the user requires the drive logics to be enabled at all times If the drive is not selected through the DS jumper and the MX jumper is not cut the drive logics are enabled but the front panel E D is not The MX jumper must be cut in a multiple drive system 3 8 pe ee ee ee POWER ON 1 SECOND MINIMUM ORIVE SELECT NIMM LS OPER SS MOTOR ON LL 250 MILLISECONDS 200 3 MAXIMUM MILLISECOND
65. p flop time is two microseconds at IC U8 Pin 10 Generation of controlling signals for correct stepping phases is accomplished via 07 direction flip flop controls the up or down counting of the step pulses two pulses per track used by IC U7 IC U8 Pin 12 when clocked by a step pulse will clock IC U7 at Pin 14 thus Pin 3 of IC U7 will trigger a l millisecond one shot at IC U8 Pin 2 which retriggers the two microsecond step flip flop IC U8 Pin 9 IC U7 is clocked again to complete a single phase rotation of the stepper motor through logic driver IC s Ul and 02 NOTES THE TIMES IN THE ABOVE DESCRIPTION ARE FOR THE 20 MILLISECOND STEPPER MOTOR FOR ADDITIONAL INFORMATION SEE TABLE 1 SHEET 1 OF 3 MOTOR CONTROL SCHEMATICS FOR COMPONENT VALUES AND CHANGES FOR SIX MILLISECOND STEPPER MOTORS PHASE 0 OF THE STEPPER MOTOR IS ACTIVE ON ALL EVEN TRACKS 0 2 4 6 Stepper Motor Control The stepper motor control circuits generate the two phases of the step sequence based information from the step and direction inputs These two phases are fed to the stepper motor drivers which produce the current through the motor s coils Stepper Motor The stepper motor is a single phase motor which rotates 3 6 degrees for each phase The capstan and split band translates this rotation to a one track linear movement of the head carriaye assembly 4 5 READ WRITE DATA The components of the drive required to read and writ
66. p screw should be adjusted after the Cats Eye pattern adjusted or when the carriage seeks to a track lower than 5 16 1 Set up the oscilloscope Channel A Test Point 4 Channel B Test Point 5 Ground Test Point 8 or 14 Read Differentially A plus B B inverted Time Base 20 milliseconds per division External Trigger Test Point 12 2 Apply power to the drive 3 Select the drive 4 Insert an alignment diskette 5 Loosen Number 1 Phillips screw at rear of Track 0 sensor Track 0 stop block slides inside of Track 0 sensor See Figure 5 13 6 Step the carriage to Track 0 and observe the waveform 7 Slowly push the Track 0 stop block into Track 0 sensor until the output amplitude begins to decrease on the oscilloscope 8 Slowly retract the Track 0 stop block until amplitude stops increasing Retract it an additional 1 32 of an inch Tighten the Track 0 stop block screw 5 11 HEAD OUTPUT CHECK The head output check measures the head s output amplitude relative to the diskette being used When using certified quality media typical values will be 200 millivolts peak to peak greater However values may be significantly less 100 millivolts peak to peak typical if inferior or defective media is used and does not indicate a faulty head Head amplitude can be verified by establishing a nominal value of amplitude for the diskette on a known working drive In all cases amplitudes greater than 200 millivolts peak to peak
67. pplicable Verify the Cats Eye pattern Step the drive to Track 0 then step it back to Track 16 Verify the Cats Eye pattern Step the drive to Track 26 or higher then step it back to Track 16 Verify the Cats Eye pattern If all the checks verify the radial track alignment is acceptable If any check does not verify the stepper motor must be adjusted 5 9 Radial Track Alignment Adjustment 1 Loosen the two Number 1 Phillips retaining screws on Stepper motor see Figure 5 7 2 Using a flat blade screwdriver between the chassis camming bar and the stepper motor rotate the stepper motor 3 Observe the Cats Eye pattern of the head farthest out of alignment 4 Adjust until the Cats Eye patterns are equal in amplitude Figure 5 6 5 Tighten the stepper motor retaining screws 6 Recheck the Radi 1 Track alignment CHASSIS CAMMING BAR 1 PHILLIPS STEPPER RETAINING MOTOR SCREWS BOTTOM OF DRIVE L FIGURE 5 7 STEPPER MOTOR RETAINING SCREWS AND CAMMING BARS 5227 INDEX CHECKS AND ADJUSTMENT The index adjustment changes the time period from the index pulse to the start of the data in hard sectored diskettes The adjustment should be checked after the drive has been aligned or when diskette interchange errors are suspected 5 10 Index To Data Pulse Checks 1 Set up oscilloscope Channel A Test Point 4 Channel Test Point 5 Ground Test Point 8 or 14 Read
68. r input retaining bracket Figure 6 4 FIGURE 6 4 POWER INPUT PLUG AND BRACKET 6 5 Push the bracket to the front of the drive and remove it The power input plug has two cables running trom it plug Number 2 is to the servo circuit board on the bottom of drive Plug Number 7 on top of the drive is to the control and data circuit board Disconnect both plugs and remove them from the drive Installation l Position the power input plug on the chassis with rounded corners to the top and next to the chassis retaining forms Route cable plug Number 2 through the hole in the chassis to the bottom of drive Cable plug Number 7 remains on the same side as the power input plug CAUTION THESE CABLE PLUGS CANNOT BE REVERSED POWER APPLIED IS NOT THE SAME PIN OUTS ON THE CIRCUIT BOARD Put the bracket over the hole in the chassis and line it up with the power input plug The bracket must engage with the chassis through the hole The power input plug goes against the chassis retaining forms Secure the bracket with a Number 1 Phillips screw into the chassis standoff Replace the chassis shield Replace the control and data circuit board WRITE PROTECT SWITCH Removal Remove Pli from the control and data circuit board Cut the tie wraps as required to route Plug Pll through the hole in the chassis to the bottom of the drive Remove the servo circuit board At the lower left front side of the drive loos
69. rner of the chassis Route cable Plug Pl through the hole in the chassis Remove the belt from the motor pulley Remove the two Number 1 Phillips screws from the bottom ot the drive below the motor Lift out the motor Installation 1 Insert the new drive motor through the hole in the chassis Line up the retaining screw holes The wires from the motor go to the rear of the chassis Insert and tighten the two retaining screws Route drive motor cable Plug Pl through the hole in the chassis to the servo circuit board Connect the cable to the circuit board Install the tie wraps as required Attach the drive belt to the drive motor pulley Ensure the drive motor drive belt and spindle pulley are rotating freely MOTOR MOUNTING SCREWS BOTTOM OF DRIVE FIGURE 6 9 DRIVE MOTOR 6 19 APPENDIX A RECOMMENDED SPARE PARTS AND MAJOR ASSEMBLIES This appendix contains the recommended spare parts list and the major assemblies Part numbers on this list should be used for ordering A spare parts list with prices for parts and services is available from Tandon Corporation Part Number Description 210375 001 Front Panel Assembly 210309 001 Diskette Lever 211019 001 Write Protect Assembly 210586 Write Protect Assembly Fast Seek 210372 001 Upper Plate Assembly 210440 001 Read Write 48 210533 001 Drive Motor Assembly 210382 001 Track 00 Sensor Assembly 210340 001 Band Assembly 2103
70. skette is write protected The tab must be removed to write on the diskette Figure 3 5 contains information on how to install a tab to cover the slot Diskette Handling and Storage It is important the diskette be handled and stored correctly so the integrity of the recorded data is maintained A damayed or contamina ted diskette can impair or prevent recovery of data and can result in damage to the read write heads Figure 3 5 contains an illustration of the physical configuration of the diskette The 5 125 inch diskette is oxide coated flexible mylar It is enclosed 5 1 4 inch square protective jacket In addition openings for the drive and diskette index hole are provided WRITE PROTECT TAB _ WRITE PROTECT 0 L FOLO OVER BACK OF DISKETTE 3 56 MM 0 14 INCH 6 30 MM 0 25 INCH 96 5 MM 3 808 INCHES INDEX ACCESS HOLE gt FIGURE 3 5 WRITE PROTECT TAB 3 13 Figure 3 6 provides some helpful hints on the care and handling of the drive diskettes In addition to ensure trouble free operation and to enhance the service life of the diskette the follow ing handling procedures should be observed DO NOT WRITE ON THE DO NOT TOUCH PRECI TO AVOID DAMAGE TO RETURN THE DISKETTE JACKET WITH PEN OR SION SURFACE WITH THE DISKETTE AND TO TO ITS JACKET WHEN PENCIL USE A FELT YOUR FINGERS YOUR DRIVE INSERT NOTIN USE TIPPED PEN DISKETTE CAREFULLY UNTIL THE BACKSTO
71. tains information on how to unpack check out in stall and operate the TM50 1 and 50 2 drives 3 1 UNPACKING THE DRIVE The drives are shipped in protective containers to minimize the possibility of damage during shipment The following list is the recommended procedure for unpacking the drive 1 Place the container on a flat work surface top side up 2 Cut the tape that holds the tab in the slot on the front side of the container CAUTION Container may spring open when the tape is cut 3 Remove the drive from its plastic 4 Inspect the drive for possible damage 5 Notify the carrier immediately if any damage is found 6 Save the shipping container for future use 3 2 PREINSTALLATION CHECKOUT Before applying power to the drive the following inspection should be conducted 1 Check to ensure the front latch rotates easily It should remain in the open position when rotated fully counterclockwise horizontal to front panel NOTE When the latch is moved to an open position the head arm raises 2 Remove the cardboard shipping insert and retain for future shipment 3 Ensure the front panel is secure 3 1 4 Ensure the drive belt is in place 5 Manually rotate the drive hub It should rotate freely 6 Ensure both circuit boards are secure 7 Ensure the connectors are firmly seated 29 MOUNTING THE DRIVE The drive has been desiyned to be mounted horizontally or vertically When mounte
72. tiple hole diskettes provide sector information through the use of an index sensor and electronics Figure 3 4 contains the diskette used with the drive This recording media is a flexible diskette enclosed a protective jacket protected diskette free to rotate within the jacket is continuously cleaned by its soft fabric lining during normal operation Loading The Diskette The drive is loaded by inserting the diskette head aperture forward into the front slot of the drive Access to the diskette loading slot is obtained by opening the front latch The diskette should be carefully inserted until it is solidly against the back stop 3 56 MM o 14iNCH 6 30 0 25 MM 0 25 0 01 INCH ee 133 4 MM 96 5 0 25 MM 5 25 INCH a 3 80 0 01 INCH 133 4 MM 5 25 INCH 133 4 MM Huis 25 INCH 771 SEALED PROTECTIVE lt JACKET OXIDE COATED SPINDLE MYLAR DISK ACCESS HOLE LINER HEAD APERTURE FIGURE 3 4 RECORDING MEDIA 3 12 CAUTION Damage to the center of the diskette may result if the door is closed when the diskette is not properly inserted This prevents reliable recovery of recorded data Write Protect Tab The drive is equipped with a write protect sensor assembly This sensor operates in conjunction with a diskette that has a slot cut in the protective jacket When the slot is covered with an optically opaque self adhesive tab the di
73. to represent the data Recording of data on magnetic medium is based on the principles of electromagnetics When current flows in a coil of wire it produces a magnetic field The field is confined in of magnetic material around which the wire is wound A narrow slot called the air gap is placed in the core located closest to the media is the magnetic field in the vicinity of the air gap that magnetizes the magnetic medium Figure 4 1 When the current is reversed the polarity of magnetization is reversed Information can be recorded on the diskette by using a double frequency code The magnetization profiles in each bit cell for the number sequence shown for FM recording are shown in Figure 4 2 When data is read the same head that writes the data is used The data stored is a digital bit representing a 0 or 1 each bit cell the first flux reversal represents a clock bit A second reversal represents a stored bit 1 The absence pf a second reversal represents a bit 0 5 ELECTRIC CURRENT ROTATION OF MEDIA FIGURE 4 1 ELECTROMAGNETIC CORE 4 1 ELECTROMAGNETIC CORE MAGNETIC FIELD OF HEAD MAGNETIC FIELD OF MEDIA BIT PATTERN I lI t l 1 1 NO UE grobe dad a e j i mm
74. to the radial alignment track 5 15 10 11 12 13 14 Confirm the position by observing the Cats Eye pattern Set up the oscilloscope to monitor the TTL signal at IC U8 Pin 4 Step the carriage back to Track l Ensure the signal at Track 1 is at least 2 5 volts Step the carriage out to the radial alignment track Step the carriage back to Track 2 Verify the logic level at IC U8 Pin 4 is less than 0 8 volt If all of these checks are satisfactory no adjustment is required If any of these checks is unsatisfactory adjust the Track O Sensor Track O Sensor Adjustment 5 10 The has 1 Loosen the retaining screws on the base of the Track O sensor Retighten the screw on the spindle side of the sensor to provide some friction on it The screw at the rear of the sensor is for the Track 0 stop see Figure 5 13 Move the sensor to the rear of drive as far as it will go Step the carriage back from the radial alignment track to Track 1 but do not restore it to Track 0 Slide the Track 0 sensor toward the spindle very slowly until the signal at IC U8 Pin 4 is at least 2 5 volts at Track 1 and less than 0 8 volt at Track 2 Chassis camming bars are located at the front and the rear of the sensor Retighten the screw on the spindle side of the sensor Repeat the Track sensor check to ensure the correct Setting has been attained TRACK O STOP ADJUSTMENT Track been Track 0 0 sto
75. urned on using Drive Select or Motor On Control lines NOTE The following jumpers are located on the read write control board Connected Not Connected Write Protect Wl The standard write protect feature is Wl removed Write protect control is inhibited with Wl installed wl Write Protect Write Protect control in response to a write protected diskette inhibits Write Gate thus disallowing the flow of write data to the read write heads X Write Protect Control is inhibited Head Type W2 W3 This option selects the type of head used W2 X Tunnel erase X Straddle erase optional W4 Through W8 W4 through W8 are not used Side Select W9 For use in double sided drives 9 Side Select For use in single sided drives TM50 1 X For use in double sided drives 50 2 NOTE The following jumper is located on the motor control board 3 11 Motor On W1 The standard operation Motor On signal controlling the drive motor The drive motor can be controlled by Drive Select when 1 is installed wl Motor Is Controlled By Motor 48 16 X Motor On or Drive Selected 3 7 DISKETTES The TM50 1 and 3TM50 2 drives use ANSI compatible 5 1 4 diskette Diskettes are available with single index hole or with multiple index and sector holes Diskettes with a single hole are used when soft sector format is required Mul
76. ven by the select logic through IC 117 Pins 5 and 6 and IC U7 Pins 11 and 10 to provide the NSEL signal at J10 Pin 5 to the servo circuit board Pin 5 This signal is buffered and inverted to activate the front panel L D If the drive is not selected through the select jumpers and the MX jumper is not cut 019 Pins 6 to 11 the drive electronics are active but the front panel L E D is not on 4 4 READ WRITE HEAD POSITIONER The components of the drive required to position the read write head s at the desired track are 1 Step and direction circuits 2 Stepper motor control circuits 3 Stepper motor Step and Direction The Step and Direction signals are derived from the host controller via interface connector J8 Pin 20 and J8 Pin 18 respectively The direction line is buffered and inverted on the control and read write circuit board and sent to the motor control circuit board via J10 Pin 1 On the motor control circuit board it is used as the D input of IC U6 Pin 12 the direction flip flop The step pulses are buffered by 117 Pins 1 and 2 and gated with Drive Select at IC U8 Pins 9 and 10 U8 Pin 8 is inverted by IC U7 Pins 1 and 2 Test Point 11 can be used to monitor the step input which is output at J10 Pin 3 to the motor control circuit board On the motor control circuit board the step pulses are used to clock the direction flip flop IC 06 at Pin 11 and the step one shot fli

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