Amstrad CPC 464 Troubleshooting Guide: Difference between revisions
Create comprehensive Amstrad CPC 464/664 maintenance + troubleshooting + capacitor guide set with full service-manual cap list, board revisions, chip-level technical detail, per RTC style guide |
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[[File:Amstrad CPC 464 (photo).jpg|thumb|right|300px|Amstrad CPC 464. Source: Wikimedia Commons.]] | |||
This guide covers diagnostic procedures for the '''[[Amstrad CPC 464]]''' (model 464, machine code Z70xxx series, 1984–1990). The CPC 464 BIOS does not implement a numeric POST code system — faults are diagnosed by symptom, by signal probing against the schematic in the [https://archive.org/details/Amstrad_CPC464_Service_Manual_1985_Amstrad_Consumer_Electronics Amstrad CPC464 Service Manual], and by the official '''Amstrad RP1 Test Pack''' (a service-engineer cartridge plugged into the expansion port). This guide adapts the official Basic Hardware Analysis flowchart from the service manual and adds field-experience faults documented by the Amstrad restoration community. | This guide covers diagnostic procedures for the '''[[Amstrad CPC 464]]''' (model 464, machine code Z70xxx series, 1984–1990). The CPC 464 BIOS does not implement a numeric POST code system — faults are diagnosed by symptom, by signal probing against the schematic in the [https://archive.org/details/Amstrad_CPC464_Service_Manual_1985_Amstrad_Consumer_Electronics Amstrad CPC464 Service Manual], and by the official '''Amstrad RP1 Test Pack''' (a service-engineer cartridge plugged into the expansion port). This guide adapts the official Basic Hardware Analysis flowchart from the service manual and adds field-experience faults documented by the Amstrad restoration community. | ||
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* [[Amstrad CPC 664]] / Amstrad CPC 6128 | * [[Amstrad CPC 664]] / Amstrad CPC 6128 | ||
* [[Capacitor Failure Symptoms]] | * [[Capacitor Failure Symptoms]] | ||
== Component-level faults (deep dive) == | |||
=== Powered from the monitor === | |||
The CPC 464 has '''no internal power supply''' — it takes +5 V and +12 V from the monitor (CTM colour or GT green-screen) through the DIN power/video lead. A completely dead 464 is therefore often the monitor's supply, the lead, or the machine's power connector rather than the computer itself. Corrosion around the video/power connector in the upper-right of the PCB and dried solder joints at the power socket are documented causes — inspect and reflow those joints.<ref name="cpc">Dorey, Andrew. [https://andrewdorey.com/post/amstrad-cpc-464-repair "Amstrad CPC 464 Repair and Restoration"]; and [https://retrohax.net/cpc-464-repairs-and-restoration/ "CPC 464 — Repairs and restoration"], retrohax.net. Source for the Z80/gate-array (40007) failure points, thermal-paste-fouled socket, monitor-connector corrosion, dried power-socket joints, power-switch debris, and cassette idler/belt faults.</ref> | |||
=== No display / garbage screen === | |||
* Reseat the '''Z80''' and the '''gate array (40007)''' — both are common failure points, and a socket contaminated with old thermal paste has been found preventing operation. Confirm the TTL logic is seeing its 5 V rail before condemning a chip.<ref name="cpc">Dorey, Andrew. [https://andrewdorey.com/post/amstrad-cpc-464-repair "Amstrad CPC 464 Repair and Restoration"]; and [https://retrohax.net/cpc-464-repairs-and-restoration/ "CPC 464 — Repairs and restoration"], retrohax.net. Source for the Z80/gate-array (40007) failure points, thermal-paste-fouled socket, monitor-connector corrosion, dried power-socket joints, power-switch debris, and cassette idler/belt faults.</ref> | |||
* Corrosion at the monitor connector can pull down the video signal; desolder-inspect and clean it.<ref name="cpc">Dorey, Andrew. [https://andrewdorey.com/post/amstrad-cpc-464-repair "Amstrad CPC 464 Repair and Restoration"]; and [https://retrohax.net/cpc-464-repairs-and-restoration/ "CPC 464 — Repairs and restoration"], retrohax.net. Source for the Z80/gate-array (40007) failure points, thermal-paste-fouled socket, monitor-connector corrosion, dried power-socket joints, power-switch debris, and cassette idler/belt faults.</ref> | |||
=== No power LED === | |||
The power switch collects debris that stops the LED lighting even when the rail is present; clean or replace the switch.<ref name="cpc">Dorey, Andrew. [https://andrewdorey.com/post/amstrad-cpc-464-repair "Amstrad CPC 464 Repair and Restoration"]; and [https://retrohax.net/cpc-464-repairs-and-restoration/ "CPC 464 — Repairs and restoration"], retrohax.net. Source for the Z80/gate-array (40007) failure points, thermal-paste-fouled socket, monitor-connector corrosion, dried power-socket joints, power-switch debris, and cassette idler/belt faults.</ref> | |||
=== Cassette deck === | |||
Idler-wheel slip and perished belts are the usual "motor runs but no load / no read" faults; replace the belts and clean or renew the idler tyre. A refurbish typically pairs this with a recap.<ref name="cpc">Dorey, Andrew. [https://andrewdorey.com/post/amstrad-cpc-464-repair "Amstrad CPC 464 Repair and Restoration"]; and [https://retrohax.net/cpc-464-repairs-and-restoration/ "CPC 464 — Repairs and restoration"], retrohax.net. Source for the Z80/gate-array (40007) failure points, thermal-paste-fouled socket, monitor-connector corrosion, dried power-socket joints, power-switch debris, and cassette idler/belt faults.</ref> | |||
== References == | == References == | ||