HP Forum Archive 19

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HP-97 diagnostics Message #1 Posted by Bruce Bergman on 24 Sept 2009, 8:59 p.m. 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

Re: HP-97 diagnostics Message #2 Posted by Michael de Estrada on 24 Sept 2009, 9:11 p.m., in response to message #1 by Bruce Bergman 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.

Re: HP-97 diagnostics Message #3 Posted by Geoff Quickfall on 24 Sept 2009, 9:16 p.m., in response to message #1 by Bruce Bergman 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

Re: HP-97 diagnostics Message #4 Posted by Bruce Bergman on 25 Sept 2009, 12:03 a.m., in response to message #3 by Geoff Quickfall 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

Re: HP-97 diagnostics Message #5 Posted by Dan W on 25 Sept 2009, 12:46 a.m., in response to message #4 by Bruce Bergman 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.

Re: HP-97 diagnostics Message #6 Posted by Geoff Quickfall on 25 Sept 2009, 1:00 a.m., in response to message #5 by Dan W 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

Re: HP-97 diagnostics Message #7 Posted by Etienne Victoria on 25 Sept 2009, 5:39 a.m., in response to message #1 by Bruce Bergman 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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