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HP85 - Printable Version

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HP85 - Gary Abernathy - 01-10-2006

I've got an HP 85 in excellent condition with most of everything that could be bought for it.
The tape drive has the common problem of the drive wheel has rotted. The tape is fine and will read if tape is held tight against the wheel to provide traction.

I need the part that provides the traction. Any idea where I could find it, or what would work?

Re: HP85 - David Ramsey - 01-10-2006

I've successfully repaired the drive wheels in desktop calc tape readers using heat-shrink tubing.

Take out the drive wheel (or tape drive assembly). Scrape off all the remains of the disintegrating drive wheel rubber. Get the bare metal wheel as CLEAN AS POSSIBLE.

Now hit your local electronics supply or Radio Shack. Find the smallest heat shrink tubing that just fits over the drive wheel. Back home, use a razor blade or very sharp knife to cut a piece just a millimeter or so less wide than the drive wheel. Slip it over the drive wheel and use a match or heat gun to shrink it.

Others have used 2 or 3 rubber O-rings of the proper size. These will probably result in a quieter drive, but the heat shrink tubing is easier to find.

Re: HP85 - Etienne Victoria - 01-11-2006


If you don't succeed in getting the part, I've put online a small procedure to rebuild it: here.

After you get your rubber wheel ready, voidware has a documented procedure to take apart and rebuild your Hp-85: here.

Greetings from France!


Re: HP85 capstan repair - Vassilis Prevelakis - 01-11-2006

For capstan repair/replacement info check

For a detailed discussion on how to take apart an HP-85 to get to the capstan (and a novel way to attach heat-shrink tubing to the capstan), check http://www.voidware.com/calcs/hp85rep.htm


For info on HP-85 related items check the links section at http://www.series80.org/#links

Re: HP85 capstan repair - Gary Abernathy - 01-12-2006

Thanks to all for the inputs. I'm sure I can now fix the problem.