"Paul Hovnanian P.E." wrote in message
...
Archon wrote:

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).

Any help? :-
http://www.hpmuseum.org/cgi-sys/cgiw...s.cgi?read=154

JC

That was a good lead. The model addressed has different sized drive
wheels, but this site lead me to one that suggested silicone rubber
tubing for a repair.

Thanks.

--
Paul Hovnanian
------------------------------------------------------------------
There's plenty of room for all God's creatures. Right next to the
mashed potatoes.

I was thinking originally that you might be able to rework the tyre from a
cassette machine pinch roller, but silicone rubber tubing might be a viable
alternative. I have used this for all sorts of little mechanical jobs like
this, and it seems to be pretty resiliant mechanically, and resistant to
chemical breakdown. I have it in several sizes that came to me from a coffee
machine outfit that I repair control boards for. It is semi-clear food
grade. If you have any trouble finding a source for a small amount, the
vending machine industry might be a good place to look.

Arfa