HP-65 - 1601A03250 - Compatibility Issues ? - Advice needed

[albertofenini]

Hi All,
this unit came with the HP-65 1333A19931 that we just restored (HP-65 1333A19931 Full restoration)
It had a sticker saying "Top Row Dead"
While we were expecting to find a row of led segments not working, it had and issue with all
the top keys (A,B, ...) and randomly the RTN key.
What happened was that pressing the A key, as example, rather the computing the 1/X function was sending the unit
in an unknown non responsive state with the display off.
It was then necessary to turn it off and on to bring it back to life.
So we decided to open it and clean it, other then rebuild the card reader.
It must said that when we put this very logic board into the HP-65 1333A19931 it was not presenting the issue.
Though we didn't try to read or write cards when this logic board was in the HP-65 1333A19931 chassis.
You can follow the work here : HP-65 1601A03250 Full restoration
We have not done anything cosmetic if not washing the keys and the chassis since this was not the goal for now
We re-assembled the issue with the top row keys was gone.
However, trying to use the card reader was generating random weird behavior
Some times it was reading, sometimes not
However as of now we haven't been able to write any card.
Then we thought of a possible incompatibility, has we had already experience, between the
keyboard logic and the other boards : card reader and logic board.
Since we had a spare keyboard logic of a previous generation unit we tried to swap
Don't pay attention to the low light led for the 2nd and 3rd digit, this keyboard already had this issue.
However, we didn't solve anything, since also this combination gives the same issues.
Surprisingly when the unit looks locked in some unknown state, it still can read cards ...
The clips are done with the spare keyboard logic ...
Any idea will be very welcome .... thanks in advance !!