3130 tape drive fallen sick

[HCART at VAX.OXFORD.AC.UK]

    Our 3130 filesystem has been almost unchanged recently, so I've not done
a tape backup for a little while.  Now a software update has arrived
in tar format, but when I try to load it, it reads the tape happily
for 30 seconds, then gives a

IO error or end of tape

message and clams up. Feeding in a new tape, or the old one again
does not restart reading.

    Similarly, when writing tar falls over, and cpio, when writing a
short test file responds (after apparently having written something
to the tape)

--1 K written
sq0: can't write tape EOF
sq0: can't rewind tape

    Does this look familiar to anyone out there? Is there any way I
can check to see if this is a software or a hardware problem?
Could it be a screw-up in /dev somehow? Any and all suggestions
appreciated.

    Thanks a lot.

    Hugh Cartwright    HCART at vax.oxford.ac.uk