The visual field guide lists it as ??? many other field guides don't list
it at all. It was the answer to question I didn't know to ask. Its a
friggin' dummy load!
If you happen to come across a DEC "skunk box" also know as the BA213
chassis which was home to MicroVAX 3300 - 3900's and some DEC System
5500's, you'll notice it has two power supplies (one on the left and one on
the right). I was restoring a MicroVAX 3400 and thought it had a "bad"
power supply. As it turned out, without sufficient load these power supplys
will not "light up." So to fix that on the 3400 I plugged a Fujitsu SCSI
drive (known power hog :-) on to the disk connector and voila, the thing
worked.
So I've been looking at a couple of 3400's that were used as a cluster and
both of them had M9060 boards installed in the last slot. These boards
provide sufficent load on the supplies to get them to both turn on. _Very_
handy gizmos.
Moral of the story, if you think you have a "bad" BA213 chassis, try
loading up the power supply a bit, and if that works, find one of these
boards and plug it into the last slot!
Another of lifes little mysteries solved.
--Chuck