Bob,
I think everyone who uses these TK50's has the 
same problems.  Between old, dirty tape drives,
and old, dirty cartridges, I guess it's a credit
to DEC engineering that these things still work 
as well as they do.  Speaking of DEC engineering,
I have found VMS to be a good tool to get the tapes
to rewind.  I have found that when they get stuck
in a computer running NetBSD, I can pull the drive
off that machine, hook it up to a VMS machine 
and do a

DISMOUNT MUA0:

and the thing starts rewinding.  I have also found
that the tape drives seem to work better in the lunchbox
cabinets, hooked up to a VS2000 or VS3100, than they do
mounted in a MicroVax with TKQ50.  The difference is 
more a statistical one than a hard and fast rule, but
I've become convinced of both of the above.  The deal with
the lunchbox cabinet may be one of power supply.  Those
power supplies can't be beat!

The trick of turning the transport with a Phillips
head is new to me, but if it works, I may be able
to rescue a few drives on the shelf with tapes in 
them that I've been unable to rewind.  Thanks for the
tip.

Doug