ICL OPD BASIC now in ROM!

[Pr0f]

I am wondering if any settings are cached in the 2K SRAM regarding the locations of things discovered in the config?

The manuals that have been scanned are missing a few pages, but I know that some information is stored in the RAM besides telephone numbers - so perhaps a list of available ROM's may be part of that? This is all guess work - we are missing so much technical info on the ICL OPD - it's fallen into the 'internet dark ages' due to it's date of release and the lack of archiving back then.

https://en.wikipedia.org/wiki/Digital_dark_age

[Chr$]

That is likely as I've noticed that resetting (removing and reinserting or shorting the 3v battery quickly) has had an effect in the past. Then the message 'Permanent store lost' appears on re-boot. I've removed everything from the CPU board and am comparing connections etc with the other working one, which also has everything removed.

[Chr$]

I replaced the other electrolytics on the m/b just in case. No difference.

I've fixed it though, sort of. I carried out the same mod on my other CPU daughter board and that one worked first time - BASIC in ROM!

I can only assume that something is flaky on the other board I was using... perhaps one of the 2x 74x chips at the top left because they were de-soldered and messed with or a trace/via is a bit temperamental. Or a connection to the m/b, who knows, the whole thing has been physically removed and re-inserted about 100 time! It's very mysterious.