HP-10 disassembly/reassembly

[[kby]]

Thanks Tony,

Perhaps when I have more time and if no eureka moment comes up before then I'll consider it. Right now it seems if I ran this test it would tell me it's either the CPU or it's not; if it is, then I have a slightly better confirmed diagnosis; if it's not then, well, it won't necessarily tell me what to look for in and of itself.

Knowing me, I'd probably want to take multiple measurements, like the trace from a "good" key and one from the "bad" keys to compare. And knowing me I'd probably put the test leads in t he wrong place the first "n" times.

I think a strategy that could work, though, for me is to get a bunch more jumper wires with pin clips and just jumper the keyboard to the CPU board. That way I'd be able to take as many measurements as I wanted for only one assembly/disassembly operation. But I don't have that many wires available right now.This would also allow me to put the scope probe close to where it really counts and not worry about any interference on the test wire run out. I suspect jumper wires between the keyboard and the connecting pins shouldn't be a major issue since they're the not-great pin contacts anyways. I agree that it would be really nice to have additional confirmation/information even if the eventual solution doesn't change.

Oh, I did decide to try swapping displays. No change in the symptoms, although the new display is definitely brighter, so any dimness observed before is not completely caused by the issue.