32K SRAM board (MB1732) troubleshooting

[Witchy]

Hi Ernest,

Well now I feel a bit embarrassed. 

I'm running my bench PSU at 9V 1.5A which gives me an input on the 12V rail on the RAM board of ~8.5V, exactly on the threshold you mention. Because one board is quite happy at this voltage I naturally assumed the other 3 were bad, but just by increasing the input voltage to 12V the previously dead boards have come to life. I wonder if this also relates to the program loading issue I had a few weeks ago. I'll test that after work.

The reason I was running that low is posts elsewhere that said people were using lower voltage PSUs to reduce the core temp of the regulators, and of course I had a working machine at that voltage too.

Now I've got 3 workers and 1 very dead one that appears to be missing some components on the main board.

Thanks for pointing me in the right direction!

Cheers

Witchy