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Full Version: Halfnut HP 41CX repair help
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I have two Halfnut HP 41CXs that both had corrosion on the I/O block and the I/O block connectors on the main PCB. I cleaned the corrosion, and managed to kind of get them working a bit before screwing the case halves back together by holding the cases together in just the right way, though some keys would be unresponsive if I didn't hold the cases together just right. The screw posts and wells look to be intact.

Now, after putting the screws back, neither calculator showed any life. I left the batteries out for a while, and then put them back in and pressed the ON button. I got the MEMORY LOST message, but it was either unresponsive to other keys or I would get strange behaviour from some keys - for example the MEMORY LOST message would shift in the display, or all the annunciators would light. I then removed and immediately replaced the batteries - the calculators showed no life. The behaviour of both units is quite similar.

Does anyone have any suggestions on what to try next?

I turns out the I/O block flex PCBs were more damaged than I thought - I tested them with an I/O block from a good HP-41, and they both worked.
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