TU58 / DECtape II: Capstan goo

Jan-Benedict Glaw jbglaw at lug-owl.de
Tue Dec 7 16:38:51 CST 2021


Some time ago, I got my hands on a DECtape II, though no tapes.
That'll change after a long time and in a few days, even multiple
tapes will come in.

  With that drive, I started some first tests. It's PSU seems to be
all fine, providing stable 5 and 12 V.

  It's board's wire wrapping is in factory settings, so baud rate etc.
is all known.

  However, when I checked the two drives capstans, they're old. One
has a crack, and as things go, they feel partially either hard or
gooey. Are there recommendations to exchange these for new ones? I
also noticed that one of the two motors rotates quite freely
(both unconnected from the board, so I'm sure they're not magnetically
braked) while the other ... can be turned without any unreasonable
torque, but it won't continue to spin at all.

  Also, when the tapes arrive, are there recommendations in case their
drive belts are gone?

  And a final question: There are three firmware versions archived for
the TU58 control board. It's a known version:

jbglaw at charon:~/customers/Glaw/VAX/DECtape II$ md5sum *.bin | sort
0e5f30a960e72c9d64174a4da8f48f50  23-294E2-00.bin
5e059396f779aef9cd80bc75a36c90b2  23-089E2-00.bin
5e059396f779aef9cd80bc75a36c90b2  jbglaw-DECtapeII-ROM.bin
a407fbb5aaa4823a92dd2bc374d1d3ae  23-389E2-00.bin

I guess I got the oldest version? Were there board changes, or could I
put in a compatible 2Kx8 ROM with any of these versions?  I guess any
firmware will probably work "good enough", but if I'd avoid known
problems (are the differences known?), I'd rather avoid them.

  But after all, I'm quite happy that all the bits'n'pieces will come
together in a few days.  Yay!



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