Re: HP 41 magnet card reader- mechanical problems- Message #2 Posted by Vieira, Luiz C. (Brazil) on 7 Dec 2002, 10:14 p.m., in response to message #1 by Martin Wahlich [GER]
Hi;
my answers would be:
1)yes, there are o-rings that fit in. If you have a measuring instrument, simply take the inner and outer diameters of the metal gearwheel where the o-rings are built. The closest measure of the o-ring, the best (try o-rings slightly tighter in the inner hole). If you feel confident, you can use a very, very, very small amount of silicon-based glue to fix the o-rings in the gear. This leads to the fourth answer I'm placing right now:
4) Yes, I had a problem like this: stuck cards. I disassembled the reader and saw that the o-rings simply moved out of the gear and touched the plastic structure. At this point I decided to use silicon-based glue: a very thin layer only where the o-ring would touch the gear, and another thin layer between them both. No more problems.
2) the other alternative shown here is fuel tubes used in modeling (planes). There are several inner and outer diameters. Many guys in here prefer these tubes; I simply did not find any of these closer to where I am.
3) I would not use lubricants. I do not remember seeing any, mostly because it's a slow-movements mechanism, moving gears are plastic over metal, and the magnetic card itself has a lot of contact points when being read or write.
I have one working reader with silicon-glued o-rings, no lubricants at all (they may leak and touch cards' surface, right?), working perfectly fine after more than fifteen years with me.
Success!
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