HP-65 more on the card reader

[albertofenini]

I agree, it looks like there is some high frequency noise there, kind of something would interfere ...
but what could possible generate that noise ?
The motor ? it was changed
The head ? it was changed
The capacitors or the resistance ? they were changed
Something on the logic board ? it was changed
I thought of a defect in the PCB ... it was changed as well
You are right, the switch program works ...
I don't think that the anode/cathode drivers can interfere that much
I could try to shield the card reader from the rest of the unit, but does it really make sense ?

On the other side, we also have a unit S/N 1333A20538 where both WA and WB looks good
but still it doesn't record anything on the card ...

We will keep trying ...