ok, it's after four, here, and I'm calling it a night. But I felt the need to briefly summarize and have to seriously thank all of you for the brilliant input and observation. I got it running and solved the zeroes problem. Based on your input, I looked more informedly at my inventory and it turned out that I had two 11/34a board sets, one of which had the fp board with it. I ended up taking js's advice and ditching the fp board and mix-and-matching 8265 and 8266 boards from the old and new sets to make a system that doesn't bus error and doesn't print weird zeroes. Also, thankfully, no more power-up hanging and manually entering ODT at 165200. (I wonder if there's something numeric that happens there that's affected by the bug?) I'm so excited that this thing is actually working again after so long -- thank you all again for the insights and interest! If anyone is really interested in debugging these "bus error / zero-inducing" cpu boards to find out what on earth was causing the problem, I'd be happy to loan them out. Heck, I might even try to do what we were talking about initially and write up some little math tests if you're really curious. It's been a really long and wonderful pdp11-filled day. See you tomorrow with more interesting hacking on the next hurdle: emulex controllers and smd disks! ttfn jake P.S. John, it was initially a Mac using screen(1) to talk to a PL2303 serial dongle. When you suggested terminal insanity, I switched out to an old CIT-101 terminal I had lying about. Same results. Although I concur with your suspicions because the dongle really fouls up talking to 2.9bsd for some reason and is, I agree, a pretty shady (insane) terminal. On Tue, Jan 27, 2015 at 6:38 PM, Don North <north at alum.mit.edu> wrote:

Johnny, I just took the defaults, thinking that maybe the real value there (that was printing as zeroes) was intact. In fact, the disk did run tests, blinking the ready light ferociously. Then reported all zeroes back :\ In a stroke of sheer weirdness, it also managed to boot 2.9BSD from an rl02! It actually ran kind of normally. Even got to multiuser mode and ran and compiled a hello world test program I typed in myself using vi! Crazy, eh? Per your recommendations, I'm going to try the small test programs with math here, shortly; thank you. Also, I grabbed a set of pdp11/34a boards from a dead (ps issues) machine. Can I plug them straight into this blackplane that's currently housing my misbehaving 11/34? Backplane markings are very faded but seem to say dd11-pk. thx jake On Tue, Jan 27, 2015 at 6:13 PM, Johnny Billquist <bqt at update.uu.se> wrote: