cak@Purdue@sri-unix (11/21/82)
From: Christopher A. Kent <cak@Purdue> Date: 17 Nov 1982 21:47:17-EST Mark, Your problem sounds exactly like the one we had when we got our LH/DHs last December. You plug it in, and the Unibus hangs; you unplug it, and everything is fine. Probably if you go a little farther, you'll find that the LH/DH has absolutely nothing to do with it -- take out the edge connector card that goes into the LH/DH and try connecting and disconnecting that from the Unibus cable, without having it plugged into the LH/DH. That was our problem. Turns out the PC etches were a bit too wide, and the Unibus INIT signal (active low) was tied to ground. We fixed it by drilling a hole in the errant trace and soldering a piece of wire wrap wire in place. Of course, when we called ACC about it, they couldn't believe it -- I believe the quote was something like "We extensively test every piece of hardware that leaves here." Hope this is it. Cheers, chris