HP-41cx Card Reader question

[wheagy]

I'm rebuilding an HP-41 card reader due to the "gummy" deteriorated card feeder roller. It's working about 50%, but I'm having an issue, I think, with the part outlined in red in this pic.
http://imgur.com/Q2QhwMy

This piece is flopping around somewhat loose and I'm not sure how it should fit. It appears to ride right above the read/write head when the unit is assembled, but I'm not sure it it's supposed to touch the head, hover just above it, or something else. When the part is in, and I plug the reader into the HP-41cx, the reader motor immediately starts running, even with the HP-41 off, and eventually just stops running. In this case it also will not allow the HP-41 to turn on either. If I leave the piece out, it seems to write a card, but when I try to read, I get a "CARD ERR" message. The piece does not appear to be electrically connected to any other part of the reader, so it seems like it might be for tension? But I'm not sure why the reader mostly works when it's removed but not when it's installed.

Can anyone tell me the function of that part and how it should fit in the plastic housing?

Thanks,

Win

 

[natcha]

Win,

You should also ask this question in the HPMuseum Forums - there are many people there who have rebuilt the card reader and can probably steer you in the correct direction.

http://www.hpmuseum.org/forum/

The HPMuseum.org site is devoted to HP Calculators.

Bill
Smithville, NJ

 

[wheagy]

Will do, thanks.

Win