Problem with HP-97 Card reader

[jbssm]

Hi,

I have this HP-97 card reader that is behaving strangely.
I've treated it for the gummy wheel and now everytime I turn on the calculator, the motor of the card reader just starts spinning.

I've checked the metal plate contacts and they seem ok. The have a resistance (not completely open) without card and when I put on a card they close one at the time.

Any idea what the problem might be?

[plasmoid]

Hello jbssm,

There are a number of different possibilities.

1.) Did the reader's motor run continuously before you worked on it? (I'm assuming here that it is definitely the reader's motor that is running continuously, and not the printer's motor.)

-if yes, then probably something wrong with the reader's circuit board, possibly the 1826-0322 IC.

-if no, then

2.) Does the rest of the calculator work properly?

-if yes, then probably something you did to the card reader or the ribbon cable that connects the card reader (that ribbon cable tends to de-laminate.) If you removed/re-soldered wires, check for solder bridges.

-if no, then

3.) Probably something else not correctly reassembled. Check all the various edge connector pins -- mis-aligned, bent or shorting pins can cause all sorts of different malfunctions.

If all else fails, you can send it to me for repair ;-)

-Richard (plasmoid)