Card Reader Repair



#9

I've tried both methods:

O-Rings

Silicone tube

I can't get the tube to not slip on the hub. I've tried super glue, but every time it slips. I know super glue is probably a bad choice. Does anyone have a good, fail safe glue for this?

I can get orings to super glue to the hub and this seems to work reliably, but I would prefer to use the tube to be as faithful in the replacement as possible.

Edited: 22 July 2012, 9:58 p.m.


#10

Hi.

I prefer using O-rings, and I successfully used them as replacement in many card readers. I once tried the silicon tube but the one I had available was eccentric and gave me nothing but headaches.

I once tried silicon-based glue to set the o-rings in place because I was afraid they might sleep sideways and block the hub, but it never happened with the ones without the glue. On the other hand, the silicon-based glue did not cause problems.

Chances are a thin layer would give you what you want.

Success!

Luiz (Brazil)


#11

I had a similar problem and solved it with some tubing. It was easy and still works great. Here is the original topic:

http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv021.cgi?read=224541#224541

#12

Tubing is probably the wrong size, 1/4" od, 1/8" id is too large. Should be 7/32" od, 3/32" id so it stretches over the hub and gives the proper od. Like this shot from the archives:

Finding a good piece of tubing that has perfect concentric form is difficult. I've bought many pieces of tubing over the years and have never found "the perfect fit". Even went so far as to buy a $40 length of medical grade silicone, it was okay but no better than the $3 piece from the hobby store. Even the piece in the above photo is not concentric, look at the 1/4" metal section of the wheel, top and bottom. The tubing is not even with the edge, as it should be.

All that said, as expected, I've found rings to be far more consistent.


#13

Quote:
All that said, as expected, I've found rings to be far more consistent.

Agreed. I'm 6 for 6 100% successful using O-rings. One repair with tubing done by someone else on one of my calcs works poorly.


#14

Thanks guys,

I think you are confirming my exact frustrations. I'm going with orings too. I've been far more successful with these as well.


#15

Hmmm, I must be the odd one out, as I've had pretty good luck with tubing, mind you I do use good silicon tubing that is oversize, then "mill" it down using a drill press and an emery stick (those things your wife uses on her nail !).

I wish someone would just make robber rollers out of silicon that is teh correct size and perfectly concentric that we could all just buy :-)

Cheers,
John


#16

So far (it's been several months now) I'm with you, John. I did try the O-rings but noticed only one was actually contacting the card and, after a few passes, they did tend to wiggle off the shaft. Some glue would help but first I tried the tubing from Ace Hardware (not silicone but fairly soft) and it worked so well I felt that was a better solution. There was more surface contact area and the card feed was very smooth. Maybe I was just lucky but the tubing I found was well-formed and very concentric so I assume the feed rate is constant. I've yet to do any worst-case testing (full data) and I don't have any factory cards to try (yet) but I've had no errors in general use so I think it's a good solution. Guess we'll see what holds up best in the years ahead.


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