HP-67 1705A01234 [erase other's cards, writes and sometime read back its own cards]

[albertofenini]

Hi Tony, Hi everyone

I did some further troubleshooting and this is what I discovered ...

WE stays LO all the time (when reading)

A known working CPU board moved in this chassis with the original card reader doesn't work
A known working CPU board AND a known working card reader moved in this chassis don't work either

This card reader in a known good chassis works with a good known CPU board
This card reader and this CPU board in a known good chassis both work fine
However, this CPU board in any of the other three faulty HP67s I have is not working except for one combination

It must be said that in this chassis the upper left and middle left screw holes (with keys face down)
are worn out, and this probably is preventing a good contact between the card reader switches and
the keyboard PCB, although the switches closes correctly when a card is read

I have reinforced these two holes by inserting a small wire before tightening the screws and it seems to
stay together well, however the calculator doesn't read nor writes, in a way it is worse than yesterday, but I think I may
have isolated the problem with the chassis

Also, after this tests and all this handling now it is not damaging cards where reading which is good

I have updated the photo album with a capture of RA and RB when reading, they look normal to me but
at the end of reading the "Error" message always shows up

One more thing I may try is to change the "screw" that goes thru the card reader wheel, when rotating that in
order to have more or less pressure on the card it does not move the wheel, so it may as well be that the
problem

Thanks for any advice you want to share, take care !!

Updated pictures here : HP-67 1705A01234