> On Sep 25, 2017, at 8:37 AM, Noel Chiappa via cctalk <[email protected]> > wrote: > >> From: Aaron Jackson > >> a PDP-11/73, M8192 CPU, two M8067 RAM, M7195 ... While playing in ODT, >> the console completely stopped responding. >> ... >> The CPU shows 1000, which I believe is fine, and means it's in ODT. The >> SLU card has 1111. I've had a Google and I believe this means it can't >> communicate with the CPU. >> ... >> Does anyone have any ideas? It was working and then it wasn't :( > > > I'm not familiar with the MXV11-B (M7195), and I couldn't turn up a manual > online, but likely those LEDs are set by software (I can't imagine how one > would turn on a "can't communicate with the CPU" bit in hardware ... unless > it's a flop that's set on power-on, and cleared by the first bus cycle to the > card)... > >
There is a user guide at http://vaxhaven.com/images/6/6d/EK-MXV1B-UG-001.pdf The LED’s are controlled by a single write only register as Noel suggests. You might try to blindly set or clear the leds with a poke to 77777524. 1 to turn the LED OFF, 0 to turn ON. By blind, I mean don’t expect any echo from ODT. ////// I had a M8192 go bad while I was using it a few months ago. One minute fine and then the next it would crash an OS sporadically crash, then failed to boot. ODT was still active, but after using it to look at a few registers or memory locations it would just start streaming garbage to the console until power reset. Confirmed it was only this card. I swapped out the DCJ-11 with no effect, so its definitely the board itself. Other than trying to vary the +5 supply to the backplane within normal margins to see if it would recover, I haven’t had a chance to work on it more. I’d definitely like to understand what form of bit or component rot is going on here when I get more time with it. Jerry
