Ulrik Smed wrote:
Hi

I have a GR-DVL140E that trashes the tape when doing backward picture
search. It runs OK in normal forward playback. I have had the drive
disassebled almost completely and re-assembled to fix a problem with
the back tension arm. I can feel that when it runs in backward search
mode, it does not break the right tape wheel, so the tape is
completely untight. If I press it lightly against the tape guide arm
to the right of the pinch roller, it runs OK. And when I remove the
pressure, the tape flaps over the top of the arm and crashes because
there is no backtension.
There is only one break at the takeup (right) tape wheel, and this is
disengaged when it runs backward. It seems it would work it this
break was engaged to provide backtension, but I don't know if this
meant to be so. It is a quite strong break, normally used to stop the
tape after rewinding, I think.

No MiniDV experts out there?

I'm really puzzled now, I just tried to fool the drive to think a tape was
inserted by covering the tape end sensors with my fingers while closing the
tape compartment. It spins the drum, loads the (not present) tape and makes
its initial short reverse running as if there was a tape inserted. But now
the break on the right tape wheel IS activated... :-S If it would just do
that with a tape inserted too, I'm sure it would work. Trying back and forth
with tape and no tape gives the same result every time, when a tape is
present the break is deactiveted and the tape trashes.

How can it tell the difference between a real tape and me cheating the tape
end sensors? Of course only one of the tape wheels rotate when there is no
tape (this stops the drive with a warning on the monitor after a short
while), but the break is activated even before the capstan moves.

--
Ulrik Smed
Aarhus, Denmark