This is a ZX External ROM with a W27C512 ROM loaded with 4 diagnostic tools.
Each ROM can be selected by using the DIP switch.
The W27C512 is electrically erasable so can be reprogrammed with other ROMs using a suitable programmer like the TL866
DIP Switch:
| 1 |
2 |
ROM |
| OFF |
OFF |
Retroleum DiagROM v1.71 |
| OFF |
ON |
Official Sinclair ZX 48k Spectrum Test ROM |
| ON |
OFF |
Official Sinclair Spectrum 128k and 128k +2 Test ROM |
| ON |
ON |
Brendan Alford Diagnostics 0.36D |
The board features a reset button, as well as a enable/disable button.
Setting to disable will allow booting from the ZX Spectrum and disable the external ROM.
Works with the ZX Spectrum 16k / 48k / 48k + / 128k / + 2 / +2A / +2B
If you are not familiar with these ROM's please read through the documentation on them from the authors website before purchasing to ensure they meet your expectations.
eBay does not allow posting of links so for each ROM Google:
- Retroleum DiagROM documentation
- There doesn't seem to be any documentation on this ROM but Brendan's ROM is based on this. See below.
- brendanalford/zx-diagnostics GitHub wiki
Depending on the fault on the Spectrum you might require additional hardware tools to assist you in repairing.
ZX Spectrum Diagnostic with LEDs:
https://www.ebay.co.uk/itm/254449796763
ZX Diagnostic internal ROM:
https://www.ebay.co.uk/itm/256486500029
Please contact me if you have any queries and I will be only too happy to answer them.