3B2 install tape woes (or: Wangtek 5125ES docs/jumper info)

Hi all-- Had a random desire to get my 3B2/600G running again over the weekend (this machine was the first computer I ever used UNIX on, for better or for worse...) after finding a working 300MB CDC Wren SCSI drive for it. (The UNIX install media for this machine only supports a very limited selection of drives -- it's possible to get the machine booting from an unsupported drive, but it requires having a running UNIX on a supported drive first, as far as I know.) Unfortunately, disaster struck halfway through the installation -- the tape drive's roller turned to mush. I checked it out before running the install and it seemed fine -- it was a solid rubber wheel -- but I guess something about actually running it caused it to break down. I managed to fix the roller, but the tape got goo all over it and despite my best efforts at cleaning it, that section of tape is unreadable so I can't reinstall. Fortunately, I have backups of the UNIX install tape files on my PC (several versions thereof, in fact)-- so you'd think it'd be a simple matter of attaching the tape drive to the PC and dd'ing over the files... but I'm not having any luck on any of the machines I've tried. I can only manage to copy over one file; attempting to write subsequent files fails. I have a failing drive w/a partial UNIX install for the 3b2 that boots about half the time, so I tried to do the same from the 3B2 w/this drive installed and it has the same problem writing >1 file, so it looks to be an issue with the drive and not the controller/OS. The drive is a Wangtek 5125ES, a 125MB (or 120MB, if you believe AT&Ts docs) drive. The error I get on from my Linux PC: dd: writing /dev/nst0: Input/output error st0: Current: sense key: Medium error Additional sense: Filemark detected Info fld=0x1 st0: Error on write filemark (I've of course tried different tapes, with the same result.) This is of course the only drive I have that's capable of writing tapes in this format, and of course the 3B2 isn't happy with any other tape drive I have... Anyone have any jumper settings for this drive? Anyone experienced this problem? Thanks, Josh