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Related Manuals for Acorn Computers Limited Winchester disk 110
Summary of Contents for Acorn Computers Limited Winchester disk 110
- Page 2 WINCHESTER DISC 110 & 130 SERVICE MANUAL Part No 0427,001 Issue 1 August 1984...
- Page 3 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). product...
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Page 4: Table Of Contents
WINCHESTER DISC SERVICE MANUAL Contents page Introduction Packaging and installation Specification Disc drive ADAPTEC ACB-4000 Winchester disc controller Host Adapter Power supply Environmental Outside dimensions Connections Disassembly and assembly Circuit description 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... - Page 5 WARNING: THE WINCHESTER DISC UNIT MUST BE EARTHED IMPORTANT: The wires in the mains lead for the apparatus are coloured in accordance with the following code: GREEN & 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 be connected to the terminal in the plug which is marked by the letter E, or by the safety earth symbol ±...
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Page 6: 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-serviceable part of the Winchester Disc unit is the Host Adapter printed circuit board. -
Page 7: Packaging And Installation
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. -
Page 8: Specification
3. Specification The Winchester Disc unit provides storage and retrieval of data and programs non-removable magnetic discs. This local storage microcomputer such as the BBC Microcomputer model B or as a fileserver for an ACORN ECONET local area network. The Winchester Disc unit consists of a 10 Mbyte (model 110) or 30 Mbyte ( model 130) hard disc drive, an ADAPTEC ACB-4000 Winchester Disc Controller, an Acorn Host Adapter Board which is an interface between the ACB-4000 and the host computer's 1 MHz expansion bus, and a power supply unit. -
Page 9: Environmental
3.5 Environmental Minimum operating temperature 0 degrees C Maximum operating temperature +37 degrees C Minimum storage temperature -30 degrees C Maximum storage temperature +60 degrees C Maximum operating humidity 80% RH at 35 degrees C Maximum storage humidity 80% RH at 55 degrees C Operating altitude 0 to 1800 metres above sea level Storage altitude... -
Page 10: Disassembly And Assembly
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 that the unit is disconnected from the mains power supply before dismantling it. - Page 11 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) is visible. Pull the connector off the light emitting diode and make a note of which way round it was fitted.
- Page 12 If 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.
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Page 13: Circuit Description
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 connectors and cables etc. This is an interface between the asynchronous SCSI interface to the disc controller board, and the synchronous 1MHz expansion bus interface host... -
Page 14: Scsi Control And Data Lines
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 collector, and are as follows: SELECT (SEL, pin 44) is an open collector signal which is asserted by the... -
Page 15: Scsi Connector Pinout (Pl2 And J4)
5.1.2 SCSI connector pinout (PL2 and J4) 0V 1 0V 3 0V 5 0V 7 0V 9 10 DB4 0V 11 12 DB5 0V 13 14 DB6 0V 15 16 DB7 0V 17 0V 19 0V 21 0V 23 } For future expansion 0V 25 0V 27 0V 29... - Page 16 The phases are as follows: Bus free phase: 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 deasserted. If SEL and BSY and RST are not asserted, that is sufficient to guarantee bus free.
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Page 17: The Reset Condition
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 I/O and deasserts MSG. -
Page 18: The St-412 Disc Interface Connector Pinouts (J2 And J0)
5.1.5 The ST-412 disc interface connector pinouts (J2 and JO) disc controller board communicates with Winchester disc connectors: J2 carries control information, and J0 carries data. J1 is not used in this implementation, but is electrically identical to J0. J2 Pin no 2 READ/WRITE CURRENT HEAD 2^3 4 HEAD SELECT 2^2 6 WRITE GATE... -
Page 19: The 1Mhz Expansion Bus
1MHz expansion "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 1MHzE (system 1MHz, pin 4) is a continuously running 1MHz timing signal. During access... -
Page 20: Winchester Disc Host Adapter
5.3 Winchester Disc Host Adapter In conjunction with the following description, reference should be made to the Winchester Disc Host Adapter circuit diagram in the Appendix. Winchester Disc Host Adapter interface between SASI/SCSI interface and the 1MHz expansion bus. It consists of address decoding and handshake control, buffering... -
Page 21: Buffering
5.3.2 Buffering The data bus (D0 to D7 of host microcomputer, DB0 to DB7 of SCSI interface) is buffered in the write direction by an octal 3-state buffer IC1 and an octal transparent latch (IC2). IC2 is enabled by Y4 of IC7 which is the write data signal, see 5.3.1. -
Page 22: Test Equipment And Formatting
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) Winchester 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". -
Page 23: Fault Finding
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. -
Page 24: Address Decoding
Disc controller board, see figure 2: +5V around 1.5A +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. -
Page 25: Fc41 Read Status
Test pin 11 IC2 with a scope and check that the waveform is not stuck either high or low. It should look like the one shown in figure 5. 7.2.3 &FC41 read status Run the following program: 10DIM P% 10 30.a 40LDA &FC41 50JMP a... -
Page 26: Fc43 Write Irq Enable
7.2.5 &FC43 write IRQ enable Run the following program: 10DIM P% 10 30.a 40LDA# 0 50.b 60STA &FC43 70JMP b 90CALL a Test pin 11 IC10 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. Pin 9 IC10 should be logic 0. -
Page 27: Bus Lines
The REQ/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. -
Page 28: Appendix
APPENDIX... -
Page 33: Winchester Disc Unit Parts List
Winchester Disc Unit parts list -SEE PAGE 29 Item Part No Description Qty Remarks *0201,580 case (base) *0201,581 case (top) *0201,582 case (rear) *0201,583 110 front panel screened 10M version *0201,524 130 front panel screened 30M version 0830,053 disc drive 10M version ~0831.107 disc drive... -
Page 34: Winchester Disc Unit Assembly Diagram
Winchester Disc unit assembly diagram... -
Page 36: Winchester Disc Unit Wiring Diagram
Winchester Disc unit wiring diagram... -
Page 38: Led Connection Diagram
LED connection diagram... -
Page 39: Winchester Disc Host Adapter Parts List
Winchester Disc Host Adapter parts list -SEE PAGE 35 Item Part No Description Qty Remarks bare PCB 0502,222 resistor 2k2 .25W +/- 5% *0572,221 resistor pack 16 pin DIL 220R/330R 1 *0573,222 resistor pack 16 pin DIL 2k2 RP2,RP3 *0571,222 resistor pack 16 pin DIL 2k2 *0800,116 IC socket 16 pin... -
Page 40: Host Adapter Pcb Assembly Diagram
Host Adapter PCB assembly diagram...
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