32-bit acorn hardware • Re: Continuing RISC PC testing/issues

Thanks for the comments.

There's something funny with the supply to the RTC: The +5V supply should be stiff enough override the battery voltage when the power is on. That suggests there's a higher-than-expected resistance somewhere likely D2? (or R130/R212 are too low...). The RTC should have most of 5V on it to allow accesses.

So I went ahead and replaced D2 anyway (I had a spare), it was a bit crusty (ended burning the simm socket, even with kapton everywhere, oh well), so now it seems okay, 4.75v~ with battery, I tested R130 and R132, they are both still bang on their rated values (in circuit).Sounds like there is either an issue around RAM (or access to). I'm tempted to buy one of those nifty SIMM slot testers that LinuxJedi put together just to have connectivity ruled in the socket, would be good to know more generally about what's happening here... I'll give the SIMM sockets another good clean.

The fact that it's crashing with no RAM fitted suggests it could be falling over while trying to detect the RAM size/configuration?

That would make sense, or reading garbage from the CMOS... I'm not very confident DEL or R key is getting through, since the power lights flash on the keyboard once and then nothing at all. I'm assuming DEL is the same keyboard code for Acorn and PS/2 keyboards.

Cheers.

Statistics: Posted by Zaspath — Wed Jul 31, 2024 1:49 pm

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