Value of 7-track TU10

[Noel Chiappa]

    > From: William Degnan

    >> a 7-track TU10 master

    > What is the model number of the TU10?

The serial number plate just says "TU10"; and it's not in its original DEC
rack, so any label/plate there is no longer available. But the front door
says "TU10 7 CHANNEL", and the head shows 7 tracks (since someone might have
changed the head, and not been able to replace the door).

    > The presence of the TU10M label along with a separate TU10 label plate
    > means the tape has the the master transport unit installed.

I prefer to actually check the Flip Chips, since one ought to do that anyway
to make sure they are all there (hence my previous description of it as a
"TU10 master drive ... [which] has all its Flip Chips"). (There's a list here:

  http://gunkies.org/wiki/TU10

including locations, if anyone ever needs it.)

    > Hopefully this will compare with the unit you're interested in and
    > assist with your assessment.

I am perfectly capable of assessing the technical situation from the technical
documentation (which is available), and have already done so.

What I really need is some idea of its value (I haven't a clue). I am aware
that its exact configuration and condition will affect the value, but I
thought "a 7-track TU10 master drive .. in good condition, [with] all its Flip
Chips" would be enough to get to the ball-park.

    > See DEC-00-TU10S-DC

I had previously looked online for that, but was unable to find a copy. Can
you point me at one? Thanks.

    > more diffs 7 vs, 9 track

AFAICT, the only significant difference is the head; the Flip Chip suite is
the same for both, since the per-channel boards are all 9-track, and simply
leave the last two bits disconnected when used with a 7-track head (see e.g.
drawing # TU10-0-09, note "9 Track Only").

Of course, the drive has to be able to say (to the controller) whether it's a
7-track or 9-track. Drawing # TU10-0-07 shows (center) an incoming signal on
pin AJ1 of the M514 board (slot 21) called "7 CH", that signal is intended to
ground the input, so there's a jumper to ground on the backplane to indicate
7/9 (A21C2, per the MM, Appendix A.5).

    Noel