The wrong compound. Back in '87, my GF had a very expensive B&O stereo
setup. Paid aTon for these "top drawer quality" components. After 3
years of little use, , the turntable made a scraping sound. I took it
apart, and found the rubber bushings the drive motor was mounted in
had deformed from the minute tension of the belt. The drive cog was
running against the motor bracket. B&O said "tough bananas".Some
quality.
A friend of mine had a 3 yr old Range Rover. The dash material cracked
and split Badly in this time. RR refused to warranty it.
Sheesh.
JR


On Sun, 02 Aug 2009 11:28:04 -0700, "Paul Hovnanian P.E."
wrote:

This isn't really an electronics repair problem. It might be better solved
on an HP calculator discussion group, if anyone knows the whereabouts of a
decent one.

I have a card reader for an HP-41C calculator (an HP 82104A). I took it out
of storage (a zip lock bag kept in a desk drawer) the other day and plugged
it in. When I fed a card through it, the card jammed and, when I pulled it
out, it had a streak of sticky goo on it. So I disassembled the reader.

It appears that the little rubber(?) wheel that feeds cards through (driven
by a motor and worm gear) has decomposed into the aforementioned sticky
goo. What were these things made out of? What would cause them to decompose
like this? Moisture? How much could there be in a sealed zip lock bag? What
would be a suitable material to use to fashion a new wheel (about 3/8" diam
by 1/8" wide).
HOME PAGE:
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