TK60 ;-) DEC CompacTape I/II bastard

Arno Kletzander Arno_1983 at
Mon Apr 4 02:43:28 CDT 2005

Michael Sokolov wrote:
> I have previously heard of people connecting TK50 drives to TK70
> controllers. Supposedly it results in better performance.  I don't know 
> if you lose the ability to write TK50 tapes this way or not.
> This is the first time I hear about the opposite combination, but I have
> to assume it works - whoever put it together obviously had it working,
> otherwise the combo you have in your hands would not exist.  MS

Er - couldn't it? It was junked, and nobody had bothered to make the cover
fit again. So it might just have been a try (say the original TK50 was dead)
to install a TK70, which didn't work and was subsequently abandoned. On the
other hand, 

Fred N. van Kempen wrote:
> The TZK50 controller (which converts TKbus to SCSI) works with
> both units.  The TK70 is smart enough to "fall back" to the
> slower TK50 data mode, so it'll just act like a faster (and
> somewhat more reliable) TK50 drive.

So it should work (and opinions differ whether the TK50 or the TK70 is more
reliable); the case front is the only issue. I see three possibilities:
-Running the thing without case (possibly bad idea, the resistor board in
the upper left seems to need constant directed air flow) or just without
front panel (ugly, things can get in)
-Widening the front panel cutout enough to accomodate the TK70 panel, or
trimming the transport's front bezel enough to fit in the hole (requires
irreversible modifications on original parts, so perhaps bad idea; however,
it looks doable without major damage)
-producing a new case front with a bigger opening (time for some

But, as I don't need it now, there is still the alternative of waiting for a
TK50 transport to fall from heaven. The TK70 could be removed from the
enclosure and used to (at least temporarily) substitute the TK50 which is
missing in our MicroVAX II (BA123 housing) in the university museum. Its
frontpanel has an opening which is big enough, curiously. (I had it home
over the weekend to repair the door hinge, st*p*d plastic pin had broken
off, hole was drilled in and a metal bolt inserted instead).

Arno Kletzander
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