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Help needed card-reader repair
09-25-2021, 08:24 AM
Post: #1
Help needed card-reader repair
Hi All,

I was repairing an HP-65 card reader, and while working on it, I seem to have lost a part and not just any part of the tiny roller. I've repaired my HP-41, HP-67 and an HP-97 card reader and am usually quite careful, but this time it got away.

Does anybody have a spare one? I'm going to try and 3D print it, but I am not confident it will be sturdy enough.

The cost for postage and package or any other fees is no problem. However, I want to get the card reader back in working order. The card reader PCB also has gone bad, but I've reverse-engineered it and am awaiting delivery. If anyone has any use for these, please drop me a line as well.

Thanks in advance,
Bas.

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09-25-2021, 03:47 PM
Post: #2
RE: Help needed card-reader repair
Which part did you lose? The ~3x2 mm white nylon roller opposite the card drive wheel?

If so, this is an easy part to fabricate in brass on a mini-lathe. 3D printing would not work due to concentricity, in other words, it would be out of round.

If you need dimensions, please let use know.
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09-25-2021, 05:19 PM
Post: #3
RE: Help needed card-reader repair
Yes, the nylon roller.

I can pick apart my HP-67 or HP-97 card reader and take measurements, but if you have these measurements, I'd highly appreciate it if you could share them.

Thanks,

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09-26-2021, 03:10 AM (This post was last modified: 09-26-2021 03:14 AM by teenix.)
Post: #4
RE: Help needed card-reader repair
In inches...

Roller diameter: 0.105
Roller Width: 0.080
Axle diameter: 0.035
Axle length (end to end): 0.170
Axle length (0.170 - 0.105) div 2 = 0.033

I'll add this info to my Classic Notes PDF

cheers

Tony
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09-28-2021, 10:09 PM
Post: #5
RE: Help needed card-reader repair
(09-25-2021 08:24 AM)wbvreeuwijk Wrote:  The card reader PCB also has gone bad, but I've reverse-engineered it and am awaiting delivery. If anyone has any use for these, please drop me a line as well.

Hi there,
do you mean that you have redesigned a PCB that could replace badly corroded card readers PCBs ?
Have you done it for the HP65 only or for the HP67 version as well ?
I know these are interchangeable but they are different (the HP67 one has a trimmer for adjusting the card reader speed) so it would be nice have both versions
Anyway, if this is the case I'm interested in buying some of these
Please let me know
take care !!

Edoardo & Alberto
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09-28-2021, 10:43 PM (This post was last modified: 09-28-2021 10:45 PM by teenix.)
Post: #6
RE: Help needed card-reader repair
That's a coincidence :-)

I designed some last week and should be here today sometime.

They don't have the variable resistor because I didn't have a board with one on it.

cheers

Tony
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09-29-2021, 03:26 AM
Post: #7
RE: Help needed card-reader repair
(09-28-2021 10:09 PM)albertofenini Wrote:  
(09-25-2021 08:24 AM)wbvreeuwijk Wrote:  The card reader PCB also has gone bad, but I've reverse-engineered it and am awaiting delivery. If anyone has any use for these, please drop me a line as well.

Hi there,
do you mean that you have redesigned a PCB that could replace badly corroded card readers PCBs ?
Have you done it for the HP65 only or for the HP67 version as well ?
I know these are interchangeable but they are different (the HP67 one has a trimmer for adjusting the card reader speed) so it would be nice have both versions
Anyway, if this is the case I'm interested in buying some of these
Please let me know
take care !!

I designed one with space for a variable transitor so that it should work for both HP-65 and HP-67. I have yet to receive the boards, but the idea is to put new components on it and only get the sense amplifier from the original board, then measure the resistance of the variable resistor or fixed resistor and set the new variable resistor to this level.

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10-02-2021, 05:28 AM
Post: #8
RE: Help needed card-reader repair
The replacement Sense PCB arrived and apart from a notch at the top right it fits nicely.

Anyone interested in building their own, everything is here:
https://oshwlab.com/wbvreeuwijk/hp-65-67...ader-logic


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