I have a very early HP41C (with all the bugs) that seems a little touchy.
Pressing some of the keys causes the display to blank (sometines with dim characters appearing incompletely on the right side if the display).
The calculator does not turn off and the display will usually reapear with a little fiddling.
Connecting a card reader to the calculator to either not turn on, or the display to fail (I havn't checked this out completely)
The calculator seems to "flex" a little more than any of the others I have and I'm suspecting that the internal structure that's supposed to hold things together has partially failed.
The calculator is otherwise in great condition and I would like to get it into a fully working condition once more.
Other observations include:
Memory corruption sometimes occurs after one of these display "events", suggesting that power to the at least part of the memory is interrupted
Occasionally an on/CLX (to try to get Memory Lost) will result in NONESISTANT. I'm wondering if this may be due to bad connections also (can't find parts of ram or rom?)
Pressing the user key firmly can often result in a "display event".
I would appreciate suggestions on how to tackle this one.