Now I’m back on my retro computers I’ve put together this quick guide for those looking to diagnose and repair ZX Spectrum computers.
Schematics and Service Manuals:
Having a set of schematics or even better a full service manual is the good thing to have before starting any repair. Fortunately for us, full schematics and service manuals for the all ZX Spectrum models are available on the web. I have my Speccy schematics printed out on the biggest paper size I’ve got access to, namely A3. The service manuals are a great place to start when looking to diagnose a fault.
Schematics and Service manuals can be found at:
World of Spectrum
Spectrum for Everyone
IC Data sheets
Diagnostic Software Tools:
Happily the ZX Spectrum has quite a few diagnostic software tools to help the would be fixer in his fault diagnostics. Most of these are based on external ROM device which avoids the need to have a fully working Speccy or the problem of loading diagnostic software from tape.
Here’s a few ROM based diagnostic tools
Brendan Alford on github has “ZX Diagnostic”
Paul Farrow of fruitcake has the following ROM tools: 128K RAM Tester & ROM Tester
he also has the official Sinclair Test ROM as well
Phil Ruston of Retroleum has the following “ZX Spectrum Diagnostic ROM”
Screw Drivers: Philips and flat blade
IC extraction tool
Power Supply (Adjustable/current limited)
Diagnostic software tools (see above)
TV Monitor/Screen (or car reversing monitor for composite video)
Anti static wrist or foot strap
IPA Wipes (no not the beer) – Isopropyl alcohol to clean edge connectors and contacts
Good web sites:
If the your own best efforts have not yet found the problem then there several good web sites that share their repair achievements where you can search. I like the following sites:
Dave Currah of Tynemouth Software
If you’re still no wiser, then try asking on one of the various Retro Computing Forums or general electronic forums in their repair section if they have one.
Remember to share as much information about the Speccy model, what it is not doing and what you have tried so far. Avoid simple statements like “Speccy not working please help”. It goes without saying that following the forums etiquette for posting will usually get you a more productive and polite response.
World of Spectrum forums
These are more general forums:
EEV Blog fourms