Amstrad PCW 8256 / PCW 8512 Service Manual

The PCW 8256/8512 Personal Computer Word Processor Service Manual is Amstrad Consumer Electronics plc's service manual for the PCW 8256 and PCW 8512, with a cover price of £8.00. It is undated and has no contents page or part number. The hosted scan has 42 PDF pages and the Internet Archive's OCR text layer: the 34 numbered pages, three chassis schematic sheets, three printer circuit diagram sheets and a repeat of the notes to service engineers. Amstrad published no separate "PCW 8000 Series" manual; the file name comes from the Internet Archive item.

Contents

The manual has no contents list. Its pages, with the printed page numbers (PDF pages in brackets where they differ):

• 1 cover; 2 safety test and specification; 3 important notes to service engineers; 4 software errors
• 5-9 diagnostic flow charts for drives FD1 and FD2: motor rotation, read error, write error, and seek error (FD2 only)
• 10 drive mechanism drawing; 11 notice that the next four pages are for information only
• 12-14 alignment checks: index burst, amplitude ratio, track 00 to 39 timing, positioning with a CE disk
• 15 FD1 schematic diagram; 16 FD2 schematic diagram
• 17 alignment chart for the monitor
• 18-19 monitor schematic diagram (PDF 18-20, split across three images)
• 20 monitor PCB, marked "danger mains voltage" (PDF 21); 21 monitor PCB component layout (PDF 22)
• 22-23 mechanical exploded view, cabinet exploded view and cabinet parts list (PDF 23-24)
• 24 keyboard circuit diagram; 25 keyboard control PCB with the key matrix (PDF 25-26)
• 26-27 CPU PCB; 28-29 CPU PCB Mk II (PDF 27-30)
• 30 PCW8256 printer mechanical parts list; 31 printer exploded drawing; 32 printer PC board (PDF 31-33)
• 33 monitor/keyboard electrical parts list; 34 electrical parts list (PDF 34-35)
• Unnumbered: three chassis schematic sheets (PDF 36-38), three printer circuit diagram sheets (PDF 39-41) and a repeat of the notes to service engineers (PDF 42)

What it settles

Specification (p. 2)

The PCW8256 has a Z80A with 256K of RAM, about 112K of which is used as a RAM disc; a green monitor showing 90 columns by 32 lines; one 3-inch "flip over" drive giving 180K per side, with room for a second; an 82-key keyboard with its own microprocessor; and an integral printer giving about 20 cps letter quality or 90 cps draft (elite pitch), with tractor feed and single-sheet loading. Separate custom microprocessors run the printer and the keyboard. The CPS 8256 serial and parallel interface is an option. The PCW8512 has 512K of RAM, giving a 368K RAM disc, and a second drive (1 MB unformatted) as standard. The software is Amstrad's word processing program, CP/M Plus with GSX, Locomotive Software's Mallard BASIC and Dr LOGO.

Service notes and safety test (pp. 2-3)

The safety test is a 4 kV flash test between the joined mains live and neutral and all accessible exterior metal, and an insulation test requiring at least 4 MΩ. Amstrad's notes say that full diagnostics are not in the manual and that in-depth fault-finding needs the R.P.3 diagnostic tool. Drive mechanisms and their boards, including a second drive, are not to be serviced; exchange units come from Amstrad. Printer parts are listed, but complete printer mechanisms are available on exchange, as are complete circuit boards. The drive alignment pages (12-14) are for information only; during the warranty period the mechanism is returned with its board.

Monitor and power supply (p. 17)

The monitor board carries the 12 V and 5 V supplies. The alignment chart sets 12 V with VR5002 and 5 V with VR5001, each to within 2%, measured at CD102 pins 2 and 3 with CD101 disconnected; then vertical size and linearity (15 mm top and bottom borders, 16 mm left and right, with the RP3 or a pattern disc), horizontal hold at 15.625 kHz, and cut-off. The equipment list is a digital voltmeter, oscilloscope, frequency counter and test pattern generator.

Parts lists (pp. 22-23, 33-34)

The cabinet parts list gives separate PCW8256 and PCW8512 part numbers. It lists the CRT as a 340AXB31 (171020) and, for the PCW8512 only, a compact floppy disc drive EME-231 (171224). The electrical parts list gives the main chips: Z8400AP processor (IC102), Amstrad 40028 (IC101), µPD765AC-2 floppy controller (IC203), Amstrad 40026 printer controller (IC701) and Amstrad 40027 keyboard controller (IC801), with eight TMM41257P-15 DRAMs for the 256K machine. The mains fuse F5001 is 2 A time-lag, 250 V (1400253). In the printer mechanical parts list, starred parts are for the PCW8512 only.

Memory options (chassis schematic, PDF p. 36)

The first chassis sheet carries Amstrad's memory options table for the CPU board:

Memory options (chassis schematic, PDF p. 36)

Memory (K)	DRAM size (K)	Link A	Link B	Link C	Link D	ICs fitted	Quantity
512	256	off	on	off	on	IC104-119	16
256	256	on	off	off	on	IC104-111	8
128	64	off	on	on	off	IC104-119	16
128	256	on	off	on	off	IC104-107	4

The other chassis sheets cover the CPU board logic, including the printer control section around the Amstrad 40026 (IC701). The printer circuit diagrams include the 24 V power connections.

Another scan

A 34-page scan of the manual (Internet Archive item amstrad-pcw-8256-pcw-8512-service-manual) lacks the chassis and printer sheets but has one extra page: a typed Mastercare sheet signed P.S. Wright, Mastercare PC+, "Fitting 4 pin CPU PCB in PCW8256 / PCW8512". It explains how to fit a replacement CPU board with a 4-pin power header: the 5-way monitor power connector is cut into a 3-way and a 2-way part, the 3-way part fitted with the yellow wire nearest the piezo buzzer, and the 2-way part fitted by its black wire pin, leaving the brown wire unconnected. The sheet is not part of Amstrad's manual.

What this manual does not contain

There is no fault-finding procedure for the computer itself; the flow charts cover the drives, and the notes refer the engineer to the R.P.3 diagnostic tool. There is no memory map or I/O port list; for those see Amstrad PCW Hardware Reference (John Elliott). The PCW 9256, 9512 and 9512+ have separate manuals.

Download: Amstrad PCW 8000 Series Service Manual.pdf

Related pages

• Amstrad PCW 9256 Service Manual
• Amstrad PCW 9512+ Service Manual
• Amstrad PCW Hardware Reference (John Elliott)