Tape Drive Capstans

Al Kossow aek at bitsavers.org
Thu Jan 29 14:18:27 CST 2015

On 1/29/15 10:55 AM, Ali wrote:
> is it that all
> tape drives (including ones manufactured now are ticking time bombs?

Tape is the bane of my existence.

All of the rubber parts will eventually soften or crack. I've mostly
seen softening on QIC drives, and roller cracking on helical DAT or Exabyte
drives. If you look on the audio tape deck forums, they claim a pinch roller
is only good for maybe five years of life. The youngest drives I use regularly
are 25+ years old. A TU58, for example, came out in the late 70's.

I don't think any manufacturer cared if a product worked for 10+ years when they
were made. This is a huge problem for archives that have huge collections of obsolete
media, like the Library of Congress.

Punched card readers are all going to fail because of all the rubber rollers in the
tape path. I've been told there is a place in LA that still has newly manufactured
rollers for Documation, but thanks to the fiasco in 2000, they're being retired.
That's why they keep showing up on eBay.

> Also how do you guys check capstans?

Pull the drive apart and examine it for the correct stiffness. I've
seen 1/4" QIC rollers turn to goo as soon as the shaft heats up so
even that can be deceptive. There is a high probability that any 1/4" or 1/2"
tape drive you have has a failed rubber part in it somewhere.

I just bought a big selection of difference sizes of Norprene tubing from US Plastics
to see how they work on various QIC drives. The first ones I'm trying are the HP 9145 and

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