TU58 yet one more time.

Mattis Lind mattislind at gmail.com
Sun May 29 15:12:55 CDT 2016

2016-05-29 20:34 GMT+02:00 Mark J. Blair <nf6x at nf6x.net>:

> My first attempt to use silicone tubing to repair my TU58 rollers was also
> unsuccessful. Maybe the material I used is too soft? Your experience
> suggests to me that I should hook up an oscilloscope to measure bit timing,
> and then adjust the roller composition and diameter to arrive close to the
> correct bit length.

It might be too soft. But the capstan doesn't look to flat when the tape is
inserted. So I am not sure.  Pin 5 on the 8085 has the read data and pin 7
is the strobe data.

Another question is how sensitive it is to speed variations. Apparently it
is. Or my tapes are bad. But I cannot tell for sure since I have no working

The encoding scheme is rather simple. And decoding is done by some analogue
electronics doing integration. Since it is a fixed capacitor value used it
can be problematic.


> --
> Mark J. Blair, NF6X <nf6x at nf6x.net>
> http://www.nf6x.net/

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