HP-65 goes on hold after reading a card

[albertofenini]

Hi Tony,

it's a behavior that few other HP-65s have shown in the past as well
Normally we have fixed this by swapping and mixing parts until they were working
Like it was a matter of finding a good match between the three main components,
the keyboard/display, the card reader and the logic

Certainly the keyboard/led plays a role in here, and we need to find out what it is
On the other side, on the keyboard/led there are only two active components, anode and cathode driver,
the two inductances for the led and the LC components ... not much to test ...

We where thinking to buy one of those portable microscope to look for bad traces, will see

There are not ICs getting warm and we are powering the units both via a rebuilt battery pack or via an external battery pack with a switch,
however the behavior seems not related to the kind of power source

We'll do more checks later today and we will let you knew
Thanks for the huge support !