HP-67 not behaving?

[markhen]

I eventually worked around to opening the calc - my findings:

- AndiGer was spot on - the restorer did leave out the screws under the label! Thanks AndiGer!!

- The PCB is in excellent shape (no corrosion etc.). I visually inspected (with magnification) all the solder joints and they are excellent. Even so, I did carefully re-solder all the ROM/RAM pin 5s per Tony's suggestion, but sadly no change in symptoms :-(

I'm surprised to see this failure in a clean working unit that was stored in a "cool, dry" drawer, but I guess age takes its toll on everything, eh?

I have some potential donor 67s that I will raid to repair this unit - it's cosmetically perfect and the card reader should still be working (since it was well restored already).

Thanks to all!