Winchester Disc 110 and 130 Service Manual
Contents
1. There are several different types of information transfer phase is determined by MSG C D and I O Table 1 shows the phases SIGNALS DIRECTION OF MSG C D I O PHASE NAME INFORMATION TRANSFER 1 1 1 data out phase initiator to target 1 1 0 data in phase target to initiator 1 0 ay command phase initiator to target 1 0 0 status phase target to initiator 0 0 1 message out phase initiator to target not used 0 0 0 message in phase target to initiator All signals active low O assertion l deassertion Table 1 Information transfer phases The information information trans handshake sequence is to request data transfer 1 target asserts 2 initiator assert 3 target deassert ts REO when data has been trans ts ACK when data is valid on bus ferred 4 initiator deasserts ACK ready for next handshake Prior to and during in direction of the Before each in the of the at the end of During each in nation transfer phase the target I O lines in such a way that these control signal transfer phases use the REO ACK handshake er each REO ACK allows the transfer of 1 to control byte The ormation transfer the signal determines th transfer as can be seen in Table 1 will set up the MSG C D and s are stable f2. POWER SUPPLY HOST ADAPTOR BOARD DISC CONTROLLER BOARD Figure 2 View from left side it is necessary to test the Host Adapter the lower PCB with the system running then the top board can be removed with all its cable connections in place Alternatively the connectors can be unplugged to ease removal of the board and then reconnected again afterwards Remove the top board by undoing the four phillips screws which hold the PCB on its four plastic pillars The Host Adapter PCB is the lower board and may be worked upon without removal If it is necessary to replace the Host Adapter PCB then it can be removed in the same way as the top board ix No further disassembly must be carried out The cover of the hard disc drive unit must NOT be removed Reverse the above procedure to reassemble the unit Do not forget to reconnect the LED cable at iii before relocating the front panel Note the LED connector must be connected the correct way round or the LED will not function 5 Circuit description The only part of the Winchester Disc unit which is serviceable by Acorn dealers is the Host Adapter PCB see appendix for circuit diagram and its 1 q S E onnectors and cables etc This is an interface between the asynchronous SCSI E nterface to the disc controller board and the sy
3. p np p amp CO 1000 1000 C OW Item Part No Winchester Disc Host Adapter parts list SEE PAGE 35 Description Qty Remarks bare PCB 1 0502 222 resistor 2k2 25W 5 1 R1 0572 221 resistor pack 16 pin DIL 220R 330R 1 1 0573 222 resistor pack 16 pin DIL 2k2 2 RP2 RP3 05 71 222 resistor pack 16 pin DIL 2k2 1 RP4 0800 116 IC socket 16 pin 3 RP2 3 4 0680 002 capacitor decoupler 47nF 16 A 0622 220 capacitor 22uF 16V 1 C2 0740 007 7407 1 16 0740 01 7414 1 1615 0740 038 7438 2 1C13 1C14 0742 000 74LS00 1 2 0742 00 74150 1 9 0742 01 74151 1 IC8 0742 07 741 57 2 CELO 1641 0742 138 7415138 2 106 1C7 0742 240 7415240 1 IC3 0742 2 7415244 2 CL LC5 0742 373 1415373 2 1C2 1C4 0800 870 connector 34 pin header 1 PL1 0800 871 connector 50 pin header 1 PL2 0800 784 right angle faston tab 2 0V 5V 32 Parts marked are available as spares 34 Contact supplier for details 82 Wall c W31I it 72 2 5 v 72 Wall 12 v re y ma wail 62 N31 5 wand S Wald vo v Host Adapter
4. 12 5 1 5 The ST 412 disc interface connector pinouts J2 and JO The disc controller board communicates with the Winchester disc via two connectors J2 carries control information and JO carries data J1 is not used in this implementation but is electrically identical to 90 J2 Pin no OV 1 2 READ WRITE CURRENT HEAD 2 3 OV 3 4 HEAD SELECT 2 2 OV 5 6 WRITE GATE OV 7 8 SEEK COMPLETE 0V 9 10 TRACK 0 OV 11 12 WRITE FAULT 0V 13 14 HEAD SELECT 2 0 0V 15 16 RESERVED 0V 17 18 HEAD SELECT 2 1 0V 19 20 INDEX OV 21 22 READY OV 23 24 STEP 0V 25 26 DRIVE SELECT 1 0V 27 28 DRIVE SELECT 2 29 30 DRIVE SELECT 3 OV 31 32 DRIVE SELECT 4 33 34 DIRECTION IN JO Pin no DRIVE SELECTED 1 2 0V RESERVED 3 4 0V RESERVED 5 6 OV RESERVED 8 OV RESERVED 9 10 RESERVED OV 11 2 OV MFM WRITE DATA 13 14 WRITE DATA 0V 15 16 MFM READ DATA 17 18 MFM READ DATA OV 19 20 OV The read and write data lines pins 13 14 17 and 18 of 90 are differential signals 13 5 2 The 1MHz expansion bus The following is a description of the 1MHz expansion bus signals used by the Win
5. Not necessarily the same shade of that colour 1 Introduction This manual is intended to provide the information required to diagnose and repair faults on the Winchester Disc unit which was designed by Acorn Computers Limited of Cambridge England The only dealer serviceabl part of the Winchester Disc unit is the Host Adapter printed circuit board Faults detected in the disc drive disc controller board or power supply mean that the faulty part must either be returned for repair or replaced Dealers may hold stock of these items and should refer to information provided by their supplier for service procedures for these units The information contained in this manual is aimed at servic ngineers and Acorn dealers who will be servicing the Winchester Disc unit on behalf of Acorn Computers Ltd 2 Packaging and installation The Winchester Disc unit is supplied fitted with two expanded polyethylene end pieces in a corrugated card box Supplied with the Winchester Disc unit is a User Guide a ROM labelled ADFS a mains lead a 1MHz bus lead and a guarantee card which are all packed in a card tray located in the top of the box The ADFS ROM must be plugged into one of the host microcomputer s sideways ROM sockets or the Winchester filing system will not work The Winchester Disc unit must be connected to a 240V AC 50Hz supply via the mains lead provided and the s
6. If for example DO to D7 are all 0V or a mixture of 0V and 2 5V then one of the buffers is probably enabled 22 APPENDIX 23 10 wisi _ nsu I X yi 9 21 0 815 y lt 4 y as UU ray 3494 viste iov 3NVWSONYH a 01 259 735 t 43 3 1 MO 5 o UU T7 73 ur 9 ASe 1 Es si Je lag 6 B 319 6 i nsi 914 x 2 d 5174 Mam z d 8 lt T lt lt H dor Y RISA 0 1 st sr x e 1 s et se tt s M m ii a u un 1 5 t an 1 250 AS ou 0 1 sm 6 2 gt ze 190 yon 190 90 so a n MEE CHIN 1596 32994 JHM aN ov iw iv v sv 9v iv 00 ta tg ta 0 Host Adapter PCB circuit diagram 25 LINN AlddNS H3MOd 2810 Cayos YILNA
7. IC7 which is the read data able for reading by They can be latched into IC4 an octal transparent The control signals appear on the data ither by IC15 or IC9 prior to being values read from the data bus are active high 5 3 3 Termination The Host Adapter for terminat RPl termina RP2 RP3 Vinchester CES and is RP4 terminate the the only peripheral peripheral in a daisy chain B carries 4 resistor packs ting the various buses and control lines the SCSI lines from the disc cont 1MHz bus lines and RP1 to RP4 which are used troller board are fitted if the on the 1MHz bus or if it is the last 16 6 Test equipment and formatting Test Equipment Required BBC Microcomputer model BD host microcomputer fitted with ADFS ROM Video Monitor Floppy Disc Drive see below Vinchester Disc unit Under Test 6 2 Formatting Drives Before shipment each Winchester Disc unit has a suite of utility programs stored on it including a formatter entitled Superform Copies of this software are available to dealers on floppy disc For details on formatting see the Winchester Disc User Guide Acorn Part No 0427 000 Not explained in the User Guide are options B and C Affixed to the drive itself is a label or labels bearing the defect list and other parameters particular to that
8. 19 Test pin 11 high or low It should look like the one AV 0V E IC2 with a scope and check that the waveform is not stuck either shown in figure 5 Figure 5 Test waveform 7 2 3 amp FC41 read status Run the following program 10DI 20 30 a 40LDA amp FC41 50JMP a 60 70CALL a Test pin 1 high or low 7 2 4 amp FC42 write select Run the following program 10DI 20 30 a 405 amp FC42 50JMP a 60 70CALL a Test pin 11 IC1 either high or with a scope and check low It should look like 20 IC4 with a scope and check that the waveform is not stuck either It should look like the one shown in figure 4 that the waveform is not stuck the one shown in figure 4 7 2 5 amp FC43 write IRQ enable Run the following program 10DIM P 10 201 30 a 40LDAF 0 50 60STA amp FC43 70JMP b 80 90CALL a Test pin 11 IC10 with a scope and check either high or low It should look like Pin 9 IC10 should be logic 0 Now run the following program 10DIM P 10 20 30 a 40LDAF 1 50 b 60STA amp FC43 70JMP b 80 90CALL a and pin 9 IC10 should now be logic 1 7 3 Handshaking that the waveform is not stuck the one shown in figure 4 To test the SEL BSY handshake use the following program 10DIM P 20 20 30 a 40LDAF 1 50STA amp FC4 60STA amp
9. drive Option B is used to input the defect list from the label in head cylinder byte format Option C is for entering the drive s parameters such as number of heads cylinders etc These options would be used for formatting a new drive or re formatting a drive which lacks a readable parameter or defect list for any reason When Superform is run it tries to read the defect list and parameter list from the drive and if successful it automatically formats the drive using this information Built into Superform is a set of default values for drive parameters which can be inspected using option C If the drive concerned differs in any respect the parameters must be typed in again Two common classes of difference are n a 10M drive RWCC could be 306 or 128 n a 30M drive the parameters for heads cylinders and RWCC will differ 10 2x0 All data stored on the Winchester Disc including the utility programs are lost after formatting 17 7 Fault finding When the Winchester Disc unit is powered up the hard disc will spin up to Speed in about 10 seconds This process produces a rising pitch humming noise which means that the hard disc is spinning Note that there is also a noise from the cooling fan but this noise is lower in pitch and does not take time to build up If the disc is not spinning then disassemble the unit and check the power
10. signal is labelled CNPGFC pin 5 IC10 The low order address lines to A7 are buffered through 1065 IC6 a 3 to 8 line decoder with three enable inputs decodes the low order addresses amp 40 to amp 43 ie output pin 15 goes low when the low order address is 840 amp 41 442 or amp 43 IC7 is another 3 to 8 line decoder which takes the output from IC6 and CNPGFC and 1MHzE as enable inputs The 2 least significant address bits AO and Al are decoded along with R NW into the required 5 separate signals shown above YO pin 15 is read data R NW 1 Y4 pin 11 is write data R NW O Yl pin 14 is status Y6 pin 9 is select Y7 pin 7 is enable IRQ All these outputs are active low When either of the two data transfer paths is selected YO or Y4 an ACK signal is generated by clocking a D type flip flop half of 11 This flip flop is cleared direct from the REQ line and thus the REQ ACK handshake is E facilitated The other half of IC11 facilitates the SEL BSY handshake The D type is clocked by Y6 to generate select and is cleared by BSY When Y7 is selected the least significant bit on the data bus D0 is clocked into a D type flip flop half of IC10 this value is a 1 then the latch 2 NANDs of IC12 is enabled and an will be generated at the ne
11. 5 2 1 Control address and data lines 5 2 2 Connector pinout 5 3 Winchester Disc Host Adapter 5 3 1 Address decoding and handshaking 5 3 2 Buffering 5 3 3 Termination 6 Test equipment and formatting d Fault finding died Power supply bed Address decoding 7 2 1 amp FC40 read data 7 2 2 amp FC40 write data 7 2 3 amp FC41 read status 7 2 4 amp FC42 write select 7 2 5 amp FC43 write IRQ enable 123 Handshaking 7 4 Bus lines Appendix Host Adapter PCB circuit diagram Vinchester Disc unit block diagram Vinchester Disc unit parts list Vinchester Disc unit assembly diagram Vinchester Disc unit wiring diagram LED connection diagram Vinchester Disc Host Adapter parts list Host Adapter PCB assembly diagram page i 00 4 01 01 0 OOO C0 CO CO CO CO NP 25 2 28 29 2 33 34 35 WARNING THE WINCHESTER DISC UNIT MUST BE EARTHED IMPORTANT The wires in the mains lead for the apparatus are coloured in 2 accordance with the following code GREEN amp YELLOW EARTH BLUE NEUTRAL BROWN LIVE As the colours of the wires may not correspond with the coloured markings identifying the terminals in your plug proceed as follows The wire which is coloured green and yellow must
12. A ACORN COMPUTER Winchester Disc 110 and 130 Service Manual WINCHESTER DISC 110 amp 130 SERVICE MANUAL Part No 0427 001 Issue 1 August 1984 BBC is used as an abbreviation for ithin this publication the term British Broadcasting Corporation Copyright Acorn Computers Limited 1984 Neither the whole or any part of the information contained in or the product described in this manual may be adapted or reproduced in any material form except with the prior written approval of Acorn Computers Limited Acorn Computers The product described in this manual and products for use with it are subject to continuous development and improvement All information of a technical nature and particulars of the product and its use including the information and particulars in this manual are given by Acorn Computers in good faith However it is acknowledged that there may be errors or omissions in this manual A list of detail s of any amendments or revisions to this manual can be obtained upon request from Acorn Computers Technical Enquiries Acorn Computers welcome comments this manual and suggestions relating to the product and All correspondence should be addressed to Technical Enquiries Acorn Computers Limited Newmarket Road Cambridge CB5 8PD All maintenance and service on Computers autho
13. FC4 70 b 80LDA 6 41 b 100RTS 110 120PRINT USR a AND amp FF Press the BREAK key followed by OLD RUN the program The LED on the disc controller board should illuminate and the result 2 should be printed on the screen after the assembler listing The result is the contents of the status register and BSY is bit Dl which corresponds to 2 nothing happens and the program is typed in correctly then there is either a loose connection or a fault in the disc controller board The system can be deselected by pressing BR 21 The REO ACK handshake operates only during data transfer If the hardware for this handshake is faulty then there can be no data transfer 7 4 Bus lines When the buses are not being asserted either by the SCSI interface or the host microcomputer ie in the bus free phase all bus lines will float according to the values of their terminating resistors Measure the voltage of each bus line in turn and make sure that none of them is stuck at 5V which would indicate a short circuit or at 0V which would indicate either that one of the buffers was enabled or that there was a short circuit The correct voltages are as follows 1 MHz expansion bus DO to D7 and to A7 should all be 2 5V SCSI DBO to DB7 should all be 3V
14. NOIOY INN YITIOYLNOD YOldvav ea un 219 18 osia ISOS ISVS 1SOH sng NOISNVdX3 ZHN Winchester Disc Unit parts list SEE PAGE 29 Item Part No Description Oty Remarks 1 0201 580 case base 1 2 0201 581 case top 1 3 0201 582 case rear 1 4 0201 583 110 front panel screened 1 10M version 0201 524 130 front panel screened 1 30M version 5 6 0830 053 disc drive 1 10M version 0831 107 disc drive 1 30M version 7 0831 102 power supply 1 8 0837 000 PCB controller 1 9 0127 000 PCB host adapter 1 10 11 0890 010 adhesive silicone rubber a r 12 0884 054 PCB support spacer 4 13 0884 053 PCB support spacer 4 14 0882 121 screws M3x6 pan hd posi 8 for PCB spacers 15 0884 140 screws 6 32 uncx3 8 pan hd 4 for disc drive 16 0884 160 washers 6 32 UNC 4 for disc drive 17 0882 974 washers M4 8 for fan and earth 18 0882 124 screws M3x12 pan hd posi 4 for psu mounting 19 0201 587 rear label 1 20 0201 586 front label 1 21 0882 223 screws 3 10 csk hd posi 2 for power socket 22 0890 000 rubber feet 4 23 0805 003 switch dpst 250V 10A 1 24 0882 121 screws M3x6 pan hd posi 13 for case assy 25 0815 902 power socket 1 26 0800 983 conr skt jk kit 2 27 0882 972 washers M3 35 28 0882 902 nuts M3 2 for power socket an
15. PCB assembly diagram 35 ACORN COMPUTER Computers Limited Fulbourn Road Cherry Hinton Cambridge 1 4JN England
16. be connected to the terminal in the plug which is marked by the letter E or by the safety earth symbol or coloured either green or green and yellow The wire which is coloured blue must be connected to the terminal which is marked by the letter N or coloured black The wire which is coloured brown must be connected to the terminal which is narked by the letter L or coloured red 4 If the socket outlet available is not suitable for the plug supplied the plug should be cut off and the appropriate plug fitted and wired as previously noted The moulded plug which was cut off must be disposed of as it would be a potential shock hazard if it were to be plugged in with the cut off end of mains cord exposed Ei The moulded plug must be used with the fuse and the fuse carrier firmly in place The fuse carrier is of the same basic colour as the coloured insert in the base of the plug Different manufacturers plugs and fuse carriers are not interchangeable In the event of loss of the fuse carrier the moulded plug MUST NOT be used Either replace the moulded plug with another conventional plug wired as previously described or obtain a replacement fuse carrier from an Acorn Computers authorised dealer In the event of the fuse blowing it should be replaced after clearing any faults with a 5 amp fuse that is ASTA approved to BS 1362
17. chester Disc Host Adapter and their function as applied to the Winchester Disc system For a full description of the 1MHz expansion bus see BBC Microcomputer Application Note Number 1 1MHz Bus part number 0407 000 published by Acorn Computers Limited 5 2 1 Control address and data lines 2 system 1MHz pin 4 is a continuously running 1MHz timing signal During access to the 1MHz bus the processor clock normally 2MHz is stretched so that the trailing edges of 1MHzE and the processor clock are synchronised R NW read not write pin 2 is the system read write line NIRQ not IRQ pin 8 is the interrupt request line which is open collector and asserted by a device pulling it low IRQ is level triggered active low NRST not reset pin 14 is output only active low system reset line It is active on power up and when the BREAK key is pressed NPGFC not page amp FC pin 10 is a signal decoded from the top 8 system address lines A8 to A15 NPGFC is an active low signal which is low when the address high byte is amp FC ie when the full address is amp 00 to amp FCFF Four locations in this range are used by the Winchester system amp FC40 to amp FC43 inclusive see 42 A0 to A7 address low pins 27 to 34 are the bottom 8 system address lines DO to D7 system data bus ar th bi directional data lines Direction determ
18. ctor and are as follows SELECT SEL pin 44 is an open collector signal which is asserted by the initiator as the first step in any transfer of data through the interface BUSY BSY pin 36 is an open collector signal which is asserted by the target to indicate that the data bus is in use This is the first response of the target to the initiator s assertion of SEL and the SEL BSY handshake is the first communication in any Winchester filing system operation CONTROL DATA C D pin 46 is asserted by the target when the bus carries control information and is deasserted when the bus carries data INPUT OUTPUT I O pin 50 controls the direction of data flow and is asserted by the target to indicate input to the initiator disc to computer and is deasserted to indicate output to the target computer to disc REQUEST REQ pin 48 is asserted by the target to indicate a request for a EQ ACK data transfer handshake J ACKNOWLEDGE ACK pin 38 is asserted by the initiator to indicate acknowledgement of a REQ ACK data transfer handshake The REQ ACK handshake provides the asynchronous timing of all data transfer between initiator and target RESET RST pin 40 is asserted by the initiator on power up and when the host microcomputer s BREAK key is presse
19. d 37 way conns 29 0815 222 fuse 3A15 F HBC 20x5mmD 2 for item 25 30 0880 072 cable clamp 2 31 0201 921 fan 1 32 0882 14 screws M4x12 pan hd posi 4 for fan 33 34 0882 904 nuts 4 6 for fan and earth 35 0885 201 fan finger guard 1 36 0779 006 stackable LED 1 37 0779 005 grmt 1 for item 36 38 0201 700 cable assy 1 live jumper 39 0201 701 cable assy 1 live jumper 40 0201 702 cable assy 1 neutral jumper 41 0201 703 cable assy 1 safety earth 42 0201 704 cable assy 1 disc drive earth 43 0880 101 cable tie 197mm 6 44 0201 706 cable assy 1 drive data 45 0201 707 cable assy 1 drive control 46 0201 732 cable assy 1 ha to controller 47 48 0201 734 cable assy 1 ha to 1MHz bus 49 0201 877 cable assy 1 LED to Winchester Parts marked are available as spares parts marked can be obtained for dealers by their supplier Contact supplier for details 28 i te de 121019 DETAL X Winchester Disc unit wiring diagram 31 SWIGOMN aWwoe SATNG v SITOdONOIW gWOt uAING 2618 SONSIOSOWNOIW SWOTI SAIMG 2518 ALVIVAS SWOTI SATING 1 SAAYWAN LI 3WIGON SI IOdOH2DIN SWAISG DSIA HALLVNMHHIL IV YO ONIYIM GAT MOHS Sa IdWVYX4 D connection diagram 33 h B L F2 00 4
20. d It causes the reset condition see 5 1 3 which immediately clears the bus and resets the system MESSAGE MSG pin 42 is asserted by the target when it issues a message byte to notify completion of a command see 5 1 2 DATA BUS DBO to DB7 pins 2 4 6 8 10 12 14 and 16 is a parallel data bus consisting of 8 signals from DBO least significant to DB7 most significant 1 byte of information is transferred across the bus with each REQ ACK handshake It is important to remember that the data lines are active low and therefore are inverted in both directions when communicating with the host microcomputer All odd numbered pins are OV and pin 34 is 5V 5 1 2 SCSI connector pinout PL2 and 44 5 Th on an fol Bus Pin no OV 1 2 DBO 3 4 1 OV 5 6 DB2 0V 7 8 DB3 9 10 DB4 0V 11 12 DB5 0V 13 14 DB6 0V 15 16 DB7 OV 17 18 OV 19 20 ov 21 22 0V 23 24 For future expansion OV 25 26 OV 27 28 29 30 OV 31 32 33 34 5V to supply test equipment 0V 35 36 BSY 0V 37 38 ACK OV 39 40 RST OV 41 42 MSG OV 43 44 SEL OV 45 46 C D OV 47 48 REQ OV 49 50 I O 1 3 Bus phases e bus has several distinct operational phases and cannot be in more than e of these phases at any given time phases occur in a prescribed sequence The reset condition can interrupt y phase a
21. failure Operation 11 Mean time be 3 6 Outside dimensions 37 degr 80 RH at 80 RH at 0 to 1800 0 to 3500 height 100mm 108mm including feet width 335mm depth 365mm 3 7 Connections 30 degrees C 60 degrees 35 degrees C 55 degrees C 10 degrees C per hour 50 000 hours 10 000 hours of typical metres above sea level metres above sea level usage Two 37 way D type socket connectors are provided for 1 connection These are on the rear panel and are labelled 1MHz bus Three removable resistor packs are OUT although they are in fact identical mounted on the Host Adapter PCI These packs are fitted as standard but n unit in the daisy chain Also on the rear panel is an EC plug for mains power input bus daisy chain IN and B inside the case for 1MHz bus termination d be retained only in the last 4 Disassembly and assembly Warning when the Winchester Disc unit is moved or worked upon great care must be taken not to drop jar or shock the unit in any way If the hard disc is broken through careless handling then the unit is unserviceable i Ensure tha dismantling i the unit is disconnected from the mains power supply before ii To service the Host Adapter PCB remove the thr small phillips screws labelled A in figure 1 underneath the front of the unit which hold on the
22. front panel The unit may be turned on its back to do this if desired but then remember that references to left and right in the following description will be reversed REAR Figure 1 Screws to remove iii Insert a hook through the grill on the front panel to the left side and pull the front panel until the the connection to the light emitting diode LED s visible Pull the connector off the light emitting diode and make a 5 note of which way round it was fitted Remove the front panel completely iv Undo the six small phillips screws labelled B in figure 1 which connect the bottom panel to the top panel the unit was turned on its back to gain access to the screws on the bottom panel now turn it back the right way up v Remove the single small phillips screw labelled C in figure 1 from the rear panel middle top near the ribbon cable vi Slide the top cover forward and off being careful not to get any of the cables or components caught in it The lug which was located by the screw in the rear panel will usually become caught in the internal cabling during this process vii The back panel can be left in place viii Two PCBs are now visible to the front left of the unit one above the other see figure 2 DISC DRIVE ENM KT we gt 7711111
23. ined by R NW The data lines are buffered and the buffer enabled only when NPGFC is active Pins 135 7 9 11 13 15 17 and 26 are OV 5 2 2 Connector pinout TOP Pin No BOTTOM OV 1 2 R NW 3 4 l1MHzE OV 5 6 For other applications OV 7 8 NIRQ 9 10 NPGFC OV 11 2 For other applications OV 13 14 NRST OV 15 16 For other applications 0V 17 18 DO 21 19 20 D2 D3 21 22 D4 D5 23 24 D6 D7 25 26 OV AO 27 28 Al A2 29 30 31 32 A5 A6 33 34 A7 14 5 3 Winchester Disc Host Adapter E In conjunction with the following description reference should be made to the Winchester Disc Host Adapter circuit diagram in the Appendix The Winchester Disc Host Adapter is an interface between th SASI SCS interface and the 1MHz expansion bus It consists of address decoding and handshake control buffering of the signals in either direction and termination 5 3 1 Address decoding and handshaking The Host Adapter decodes 4 locations in the host microcomputer s page FC I O space These four locations are as follows Address Read Write amp FCAO data data direction determined by R NW amp FC41 status amp FC42 select amp FC43 enable IRQ Page FC is decoded in the host microcomputer and this is available to the Host Adapter as NPGFC not page FC NPGFC is synchronised with 1MHzE by the de glitch circuit half of IC10 and the clean
24. ive an ADAPTEC ACB 4000 Winchester Disc Controller Board which is an interface between the B 4000 and the host computer s 1 MHz expansion bus and a power supply unit contains a 240V AC fan for cooling 3 1 Disc drive Capacity 10M model 110 or 30M model 130 formatted Format ADAPTEC 33 sectors of 256 bytes Cylinders 306 10M version Heads 4 10M version Disc rpm 3600 3 2 ADAPTEC ACB 4000 Winchester disc controller Disc interface ST 4 Host interface SCSI 3 3 Host Adapter 5 CSI 1 2 to 1 MHz expansion bus 3 4 Power supply Minimum input voltage 198V AC Maximum input voltage 264V AC Supply frequency 47 to 53Hz 4 9 to 5 2V 0 7 to 3 5A 5V output voltage 5V output current 5V overvoltage pro 5V overcurrent pro 12V output voltage output current surge output c overvoltage protect overcurrent protect 11 4 0 6 urren tection 5 8 to 7 0V tection 5 0A to 12 6V to 3 0A t 5A for 15 seconds tion 13 0 to 16 0V tion 6 0A The unit also 3 5 Environmental Minimum operating temperature 0 degrees s C Maximum operating temperatur Minimum storage temperature Maximum storage temperature Maximum operating humidity Maximum storage humidity Operating altitude Storage altitude Thermal gradient etime ore
25. nchronous 1MHz expansion bus nterface on the host microcomputer used by the Winchester Disc filing ystem The following circuit description will provide enough information about the disc controller board and the 1MHz expansion bus to allow a full u nderstanding of the operation of the Host Adapter board For the full specification of the SCSI interface s the relevant literature 5 1 The disc controller board The disc controller used in the Winchester Disc unit is a device which will 5 a end or accept parallel byte data to or from the host microcomputer via 1MHz bus and Host Adapter and will read or write this data serially to or rom the hard disc It contains a 256 byte cache memory hereafter referred to s the sector memory because 1 disc sector 256 bytes A connection diagram for the disc controller board is given in figure 3 below CONTROL DATA HOST INTERFACE d AL OS DATA gt DRIVE 1 D C POWER Figure 3 Disc controller board connection diagram In the following description the Host Adapter is known as the initiator and the disc controller is known as the target 5 1 1 SCSI control and data lines The 8 control and 8 data lines on the SCSI side of the controller shown on the right side of the Host Adapter circuit diagram in the appendix are all active low open colle
26. nd is always followed by bus free Any other phase can also be Llowed by the bus free phase The prescribed sequence is from bus free to selection to one or more of the information transfer phases to bus free again There are no restrictions on the order of information transfer phases and a phase will often follow itself eg two data phases one after the other A typical sequence would be bus free select controller selection phase transfer command bytes command phase transfer data bytes if necessary data in out phase st me atus phase ssage phase 10 The phases are as follows Bus free phase deasserted SE Selection phase bus free the initiator asserts SEL The target detects 1 and I O deasserted and responds by asserting S guarantee bus free L and BSY and RST are not asserted allows the initiator to select EL and may then change the data signals ormation transfer phases allow transfer of the target EL asserted and BSY BSY The initiator deasserts indicates that the bus is available for use The bus free phase is indicated by all control signals described in section 5 1 1 being that is sufficient to After detecting information across the bus and the type information transfer
27. ocket at the rear of the unit A mains power switch is located at the rear of the unit A 3 15A type F fuse is located in a holder beneath the mains socket at the rear of the unit The Winchester Disc unit must be connected to the host microcomputer s 1MHz expansion bus socket using the ribbon cable provided There is a green activity lamp on the front panel which illuminates when the drive is being accessed The Winchester unit is fragile and must not be subjected to any shock Do not use the unit in conditions of extreme heat cold humidity or dust or in places subject to vibration Do not block ventilation in front of or behind the unit especially the fan intake at the rear Ensure that no foreign objects are inserted through any openings in the case Do not move the unit while it is operating The unit must be transported in its original packing which must be retained for future use 3 Specification The Wi microcompu n non removable ACORN ECONET local nchester Disc unit provides storage and retrieval magne tic discs This can be local sto of data and programs rage for a ter such as the BBC Microcomputer model B or as a fileserver for an area network The Winchester Disc unit consists of a 10 Mbyte model 110 model 130 an Acorn Host Adapter or 30 Mbyte hard disc dr
28. or 450ns before first handshake and remain valid until the deassertion of ACK ormation transfer phase the the last handshake deasserted 11 BSY line remains asserted and 51 GI Each information transfer phase is as follows Command phase allows the initiator to direct the subsequent action of the target by transferring command bytes The target asserts C D and deasserts MSG and I O Status phase allows the initiator to read the target s status information The target asserts C D and and deasserts MSG Data out phase allows data to be transferred from initiator to target The target deasserts MSG C D and I O Data in phase allows data to be transferred from target to initiator The target asserts I O and deasserts MSG and C D Message out phase not used by the system available for future expansion Message in phase allows the target to send a message byte to notify completion of a command 5 1 4 The reset condition The reset condition is caused by the assertion of RST and immediately clears the bus and resets the system Regardless of the prior bus phase the bus resets to the bus free phase The Winchester controller reads the drive s parameters off the disc Reset can occur at any time and takes precedence over all other phases and conditions In practice it occurs on power up or when the BREAK key is pressed
29. r the yellow cable 412 The connections to the meter to do this must be made with the power switch off The measurements must be made after power up as some of the circuitry when working correctly will alter its current consumption with time as shown below The current drawn by each component from each voltage rail should be as follows Winchester hard disc unit see figure 2 5V around 1 to 1 5A 12V up to 4 5A on power on falling to around 2A when up to speed 18 Disc controller board see figure 2 5V around 1 5 12V around 250mA Host Adapter board see figure 2 5V around 500mA 12V zero not used The above figures are approximate and will enable checks to be made for open short circuits and malfunctioning components 7 2 Address decoding The easiest way to test the address decoding is to execute a program which accesses the relevant memory location 7 2 1 amp FC40 read data Run the following program 10DIM P 10 20 30 a 40LDA amp FC40 50JMP a 60 70CALL a Test pin 1 IC3 with a scope and check that the waveform is not stuck either high or low It should look like the one shown in figure 4 AV 0V 1 33 use qe 8 5 1 250 kHz Figure 4 Test waveform 7 2 2 amp FCA0 write data Run the following program 10DIM P 10 20 30 a 405 amp FC40 50 a 60 70CALL a
30. rised dealers whatsoever for any loss or dam unauthorised personnel This manu the use of this product and the for any loss or damage whatsoever the product must be carried out by Acorn Acorn Computers can accept no liability age caused by service or maintenance by al is intended only to assist the reader in refore Acorn Computers shall not be liable arising from the use of any information or particulars in or any error or use of the product This manual is for the sole use omission in this manual or any incorrect of Acorn Computers authorised dealers and must only be used by them in connection with the product described within ACORN and ECONET are trademarks of ACORN Computers Limited First published 1984 Published by Acorn Computers Limited WINCHESTER DISC SERVICE MANUAL Contents 1 Introduction 2 Packaging and installation 3 Specification S Disc drive 3 2 ADAPTEC ACB 4000 Winchester disc controller 343 Host Adapter 3 4 Power supply 35 Environmental 31 6 Outside dimensions 3 7 Connections 4 Disassembly and assembly 5 Circuit description Did The disc controller board 5 1 1 SCSI control and data lines 5 1 2 SCSI connector pinout PL2 and J4 5 1 3 Bus phases 5 1 4 The reset condition 5 1 5 The ST 412 disc interface connector pinouts J2 and 90 3 2 The 1MHz expansion bus
31. supply and connections Make sure that the ADFS ROM is plugged into one of the test BBC Microcomputer s sideways ROM sockets If the machine will not access the Winchester then type ADFS If the unit powers up correctly but still won t work then print out the contents of the status register as follows PRINT amp FC41 The result should be zero If the result is FF then the ribbon cable is disconnected 7 1 Power supply The three major components of the Winchester Disc unit the disc drive the disc controller board and the Host Adapter board are each powered from the switch mode power supply unit which sits at the back left of the case Th power supply output cables are colour coded as follows black ground red T5V yellow 12V The power supply can be tested by measuring the 5 voltage between the black and red cables and the 12 voltage between the black and yellow cables The allowable voltage ranges are as follows H5V black and red 4 9V to 5 2V H12V black and yellow 11 4V to 12 6V These measurements should be made with all connectors in place Next measure the current drawn by each of the three components specified above from the 5V and 12V supplies Two of the components are each supplied via four way plug in connector and the current measurement should be made in series with ither th red cable 5V o
32. xt falling edge of REQ To disable interrupts Y7 is selected with a 0 on DO IROs are enabled only for a very short time around 10ms when ensuring a sequential file buffer 15 5 3 2 Buffering The data bus buffered in the write direction by an octal 3 s transparent latch IC2 IC2 is enabled by 4 of signal see 5 3 1 Because IC2 is a transparent 1 on the output side when th nabl gated through 8 open coll control line of the SCSI is DO to D7 of host microcomputer DBO to DB7 of SCSI interface is tate buffer 1 and an octal IC7 which is the write data latch data will remain valid deasserted The outputs from IC2 are data across the Host Adapter requires that both R NW 0 The data bus is buffered and inverted in the rea State inverting buffer which is enabled by YO of signal see 5 3 1 A The control signals used by the SCSI the host microcomputer latch when it is enabled by 1 of bus in the following positions DO MSG Dl BSY D2 D3 D5 REQ D6 I O D7 C D All these control signals are inverted latched so all 0 0 DA NIRO see 5 3 1 RI LO interface are avail lector NAND buffers which are enabled from the I O interface and which invert the bus signals To write I O 1 d direction by an octal 3
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