squeal continuously as long as they're attached to
the SCSI bus
The SCSI cable is backwards.
I ran into this a few weeks ago.
You should also think about cleaning the heads. The easiest, totally
non-obvious way is pop the two C washers (with the power off obviously
on the head stack, and pull the stack up to gain access to the head
surface.
Clean with "head cleaner" if you can still find a bottle, or 99% isopropyl
--
TK50 media sucks.. I just had to read several hundred carts from the mid
80's and every one was sticky. The REALLY annoying thing about serpentine
media is you get to spread accumulated gunk across the ends of the tape
after each pass, and risk the motor stalling and leaving a big pile of
gunk after each direction reversal.