Editing Amstrad PCW 9512+ Troubleshooting Guide

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[[File:Amstrad PCW9512 Plus main PCB layout.png|thumb|right|360px|PCW9512+ main board, top view (service manual p. 16)]]
Amstrad's service manual for the [[Amstrad PCW 9512+]] has no fault-finding chart; its service route was the RP6 diagnostic, which the alignment chart calls for, and board or mechanism exchange.<ref name="sm9512p">Amstrad plc, ''PCW9512+ Personal Computer Word Processor Service Manual''. Hosted as [[:File:Amstrad PCW 9512 Plus Service Manual.pdf]], described at [[Amstrad PCW 9512+ Service Manual]]. Technical specification p. 2; alignment instructions with Fig. 2-1 and Fig. 2-2 p. 3; printer sub-assembly parts lists pp. 6–15; main board p. 16 (PDF p. 15); monitor/CRT board p. 18 (PDF p. 17); electrical parts list p. 34 (PDF p. 28) onwards.</ref> The checks below use its alignment figures and parts list, John Elliott's description of the PCW hardware, and the user manual of the earlier 9512, whose printer and start-up behaviour the 9512+ shares. Adjustments are in the [[Amstrad PCW 9512+ Maintenance Guide]].

'''Warning: the main unit contains the mains power supply and a CRT.''' Read [[CRT Discharge Procedure]] before opening it.

== Start-up ==
The PCW has no boot ROM. At reset the hardware feeds the Z80 a short boot program that loads the first sector of the disc; daisywheel PCWs use their own version of that program.<ref name="jehw">John Elliott, ''PCW Hardware''. Hosted as [[:File:PCW Hardware Reference (John Elliott).pdf]], described at [[Amstrad PCW Hardware Reference (John Elliott)]]. Section 2 (the dot matrix and daisywheel boot programs), sections 8.2–8.3 (drive decoding on the 9256, 9512+ and 10, and the probe in later LocoScript and CP/M).</ref> A blank screen with no disc inserted is normal.<ref name="acuc">Richard Lloyd, PCW article ("Fifty two years and counting"), ''Amstrad CPC User Club Magazine'' (ACUC) issue 1, June 2022. Scan at [https://archive.org/details/Amstrad-CPC-User-Club-01--ACUC-Magazine- archive.org]. Retrieved 2026-10-02. Boot behaviour with and without a disc; the non-standard drive power cable when fitting a Gotek.</ref>

{| class="wikitable styled-table" style="width:100%; text-align:left;"
|+'''Start-up symptoms'''
! Symptom !! Probable cause !! Action
|-
| Nothing at all || No mains, F5001 open, or a supply fault || Check the mains lead. Check F5001 (3.15&nbsp;A time-lag); if it has blown, look for the short before fitting a new one. Then measure the supply outputs (below).<ref name="sm9512p" />
|-
| Beeps, or the screen flashes, with a disc inserted || Not a start-of-day disc for this machine, or a damaged disc || Try a known-good system disc made for the 9512+. The 9512's manual says start-of-day discs for the 8256, 8512 or CPC 6128 cannot be used on it, and dot matrix and daisywheel PCWs use different boot programs.<ref name="ug9512">Amstrad, ''PCW9512 Ordinateur Personnel Traitement de Texte – Manuel de l'utilisateur'' (1987, French). Hosted as [[:File:Amstrad PCW9512 User Manual (1987, French).pdf]], described at [[Amstrad PCW 9512 User Manual (French)]]. Annex II, troubleshooting, pp. 37–41.</ref><ref name="jehw" />
|-
| Screen clears or the machine stops responding || Software crash || Remove the disc and reset with Shift, Extra and Exit; if that fails, switch off, wait and switch on again.<ref name="ug9512" />
|}

== Power supply ==
The supply is built round the STK7309 hybrid (IC5001) and switching transformer T5001, with L78MG regulators at IC5002 and IC5003, an L7824V at IC5004 and an L7812V at IC5005. The mains fuse is F5001 and the reservoir capacitor C5005, 150&nbsp;µF 400&nbsp;V.<ref name="sm9512p" />

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''Supply outputs at connector A, CP102 disconnected (service manual p. 3)'''
! Output !! Load !! Expected !! Adjust with
|-
| 24&nbsp;V || 1.2&nbsp;A || 24&nbsp;V ±1.2&nbsp;V || No adjuster
|-
| 12&nbsp;V || 1.2&nbsp;A || 12&nbsp;V ±0.01&nbsp;V || VR5002
|-
| 5&nbsp;V || 1.8&nbsp;A || 5&nbsp;V ±0.05&nbsp;V || VR5001
|}
<ref name="sm9512p" />

* F5001 blown: look for a short at the mains rectifier, C5005 and the STK7309 before replacing it.
* 24&nbsp;V out of tolerance: there is no adjuster; check the L7824V (IC5004).<ref name="sm9512p" />
* An output that is noisy or will not adjust: see the [[Amstrad PCW 9512+ Capacitor Replacement Guide]] and [[Capacitor Failure Symptoms]].

== Monitor ==
{| class="wikitable styled-table" style="width:100%; text-align:left;"
|+'''Picture faults and the matching adjustment (service manual p. 3)'''
! Symptom !! Check !! Amstrad's figure
|-
| No raster, or the picture will not lock horizontally || Horizontal oscillator at pin 5 of CP401, free running || 15.625&nbsp;kHz, set with VR4005
|-
| Picture too tall or too short || Vertical size with the RP6 or pattern disc || I = K = 10 ±3&nbsp;mm, with VR4002; VR4003 if the H spacings differ
|-
| Uneven line spacing || Linearity, set by the deflection yoke position || A−B and J−L each 3&nbsp;mm or less
|-
| Background glows with brightness and contrast at minimum || Sub-brightness || A dim pattern, set with VR4006
|}
<ref name="sm9512p" />

The CRT is an MN1416H22AU (272637); the deflection ICs are an LA1385 (IC4001) and an AN5753 (IC4002).<ref name="sm9512p" />

== Disc drive ==
The drive is a U0DC-45A (272508), 3.5-inch 720K, the same part number as the 9256's.<ref name="sm9512p" /> Elliott records that on the 9256, 9512+ and PCW 10 the controller reports drive 2 as always ready and that selecting drive 3 selects both drives at once.<ref name="jehw" /> The manual gives no drive adjustments; see [[Floppy Drive Repair]]. A Gotek fitted in place of the drive needs its power lead checked first, because Amstrad's drive power wiring is not the PC standard.<ref name="acuc" />

== Printer ==
The user-level printer faults, from a missing ribbon to paper that will not autoload, are the same as on the 9512 and are tabulated in the [[Amstrad PCW 9512 Troubleshooting Guide#Printer|9512 troubleshooting guide]].<ref name="ug9512" /> Amstrad's parts lists for the mechanism:<ref name="sm9512p" />
* Hammer drive: the hammer magnet assembly (177100), armature (177166), hammer (178124) and hammer stop rubber (178125). The hammer current is set with VR701, with the RP6 printer test running, until the pulse waveform is 2.4&nbsp;V; check it after any work on the hammer drive.
* Wheel selection: the selection motor assembly (177102) and selection sensor assembly (177101), on the print head base with the wheel holder (178122).
* Carriage: the carrier motor assembly (177086) and the drive belt (178174, or 177087 complete with its holder).
* Control: the printer is powered and controlled from the main unit, so a completely dead printer can be the cable or the printer control circuit (IC701, AMS40088) as well as the mechanism.

The Canon BJ-10e offered with the 9512+ is a standard Centronics printer with its own 240&nbsp;V adaptor, and connects to the parallel port.<ref name="sm9512p" />

== Keyboard ==
The keyboard has its own board (MK0004) with the AMS40027 controller (IC801) and a DIN cord (CD008, part 177004).<ref name="sm9512p" /> The PCW keyboard sends its data serially on a data line and a clock line that both idle high.<ref name="jehw" /> Check the cord and plug before the controller.

== Related pages ==
* [[Amstrad PCW 9512+]] · [[Amstrad PCW 9512+ Maintenance Guide]] · [[Amstrad PCW 9512+ Capacitor Replacement Guide]]
* [[Amstrad PCW 9512 Troubleshooting Guide]] · [[Amstrad PCW 9256 Troubleshooting Guide]]
* [[Floppy Drive Repair]] · [[CRT Discharge Procedure]] · [[Capacitor Failure Symptoms]]

== References ==
<references />

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