Exabyte 8505 XLS can't read old tapes

[Andy Howell]

After years of service, my tape drive died. I got a replacement one out 
of an IBM box, and I can't get it to read old tapes. I can write new 
ones just fine. If I try amrestore, it an error:

amrestore: error reading file header: Invalid argument

mt -f /dev/rmt/0 status gives:

Vendor 'EXABYTE ' Product ' IBM-8505        ' tape drive:
    sense key(0x0)= No Additional Sense    residula= 0   retries= 0
    file no= 0   block no= 0
Any ideas what might be wrong? I'm getting rather nervious, as I have 
not be able to do backups for a couple weeks.

The old drive suddenly started ejecting tapes as soon as they were put 
in. I tried cleaning it, but no luck.

Thanks,

	Andy