HP-97 diagnostics



#8

So, I just picked up a nice condition HP-97 and have found only two issues with it. I wonder if anyone can point me at roughly what I need to consider as far as repairs.

1) Inserting a mag card. It doesn't grip well, although I hear the motor run. Upon ERROR, removing the card shows little patches of stickiness (technical term) on the bottom edge of the mag side. I presume something is gummed up inside.

2) The printer works well, but advancing the paper it "sounds" a bit like it's not cleanly (or perhaps confidently) advancing. No real issue here, but is there some preventative maintenance I can do to perhaps help the situation?

Thanks!
bruce


#9

1) Needs "gummy wheel" repair. Others on this forum can tell you how. Meanwhile, don't insert any more cards until this is fixed.

2) Could just need a good internal cleaning, or could be a bad printer advance gear. If the latter, I can tell you where to get a replacement.

#10

Hello Bruce, good find!

Three things to consider here:

CARD READER:
a. the drive roller rubber has deteriorated to a gummy
residue and needs replacing.
b. the dampening couple needs replacing as it is composed of the
same rubber.

PRINTER:
c. some printers have a carbon composite gear while some have
a rubber gear composed again of the same rubber as in (a)
and (b)above.

Check out the repair section of the MoHPC:

repair section


Example of a deteriorated drive roller, some talk about a bacterial infection of the natural rubber.

Example of repair types with tubing or o-rings:

Gratuitous photo of a 97 and 91 restored:

Cheers, Geoff


#11

Thanks guys! I figured the card reader was indeed the "gummy wheel" repair scenario, but just never encountered it as yet. Lucky I guess. I have ordered some parts for the repair from YouKnowWho here and will be tackling it when I get them.

Oh, and I didn't know the museum HAD a repair section! After all these years, there's new stuff to learn every day! ;-)

Thanks!
bruce


#12

Quote:
Thanks guys! I figured the card reader was indeed the "gummy wheel" repair scenario, but just never encountered it as yet. Lucky I guess. I have ordered some parts for the repair from YouKnowWho here and will be tackling it when I get them.

Oh, and I didn't know the museum HAD a repair section! After all these years, there's new stuff to learn every day! ;-)

Thanks!
bruce


I don't know YouKnowWho, but the o-rings are very common 1/16 ID, 1/4 OD. You can find a couple at any hardware store for a buck or so.

I've repaired quite a few card readers and experimented with the o-rings and the tubing. I had more consistent success with the o-rings. They are manufactured to tight tolerances, whereas tubing is not manufactured to be perfectly round at all.


#13

Hi there again,

I prefer the tubing myself. It has greater surface area for tracking the card through the reader. I use MIL spec fuel line tubing which for some military reason has the hole in the exact centre. It is usually pink in colour.

Dan is correct though, the o-rings are consistent and easy to source.

Cheers, Geoff

#14

Hi Bruce,

Answering your question 2), this is how I repair the printer gear:

Topcat printer gear repair.

Credits go to Katie as she was the first one to publish an elaborate repair procedure.

Best regards

Etienne


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