HP-85 belts/Capstan repair

From: Michael Grigoni <msg_at_computerpro.com>
Date: Mon Mar 8 14:45:47 1999

Greetings to all:

Since I've been absent for about a week, 800 messages have piled-up
from the list; reviewing them will take awhile so I'm posting this
to report on the HP-85 belt/capstan issues status globally.

The belts have arrived and are being mailed-out early this week. I
installed a set in our HP-85 and they work well.

I tried a new approach to capstan repair which I find works very well.
Clean the capstan of old rubber down to a minimal amount of residue
with isopropyl. Obtain a can of dipping vinyl (for coating tool
handles, etc.); most hardware stores should have it. Remove the
capstan/encoder wheel ass'y from the motor shaft. Prepare the
vinyl properly according to directions with the product. Dip the
capstan (inverted) at the rate of about 5 seconds for its length,
being careful to just dip just above the bottom rim of the capstan
wheel so that the vinyl creates an overlap of 90 degrees. Withdraw
the part at the same rate as insertion. Immediately invert the
part and place on a level surface in a warm place to dry for four
hours. During the drying time you will note that any vertical
asymmetry evens out. Repeat with another dip and 4 hour dry.

The results were very good and tests with an old tape containing
an 84 record program produced no errors (reading or writing).

Attached is a small jpg which gives an idea of the appearance of the
results (max mag. avail with the camera lens).

Michael Grigoni
Cybertheque Museum
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Received on Mon Mar 08 1999 - 14:45:47 GMT

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