Hi, All, I've finally tracked down the simplest problems in my PDP-11/04 that's been sitting unused for many years (the one that we formerly used as a hardware test platform for Unibus COMBOARDs 30 years ago). The primary faults were a half-bad 7474 in the console (the flip-flop attached to the Run LED was not toggling when it should) _and_ an apparently bad DL11-W that isn't passing grant - for now replaced with a fully-functional module, but to be debugged later). What's happening now, since I can finally enter octal at the console, is when I change one location, 000000 for example, it echoes across multiple locations... To whit: I use the console to fill 000000 to 000040 with zeros, and verify they are all zeros. I deposit 177777 in 000000 and I get back the following... @L 1000 @D 177777 @L 1000 @E 001000 177777 @E 001002 004000 @E 001004 004000 @E 001006 004000 @E 001010 004000 @E 001012 004000 @E 001014 004000 @E 001016 004000 @E 001020 177777 @E 001022 004000 @E 001024 004000 @E 001026 004000 @E 001030 004000 @E 001032 004000 @E 001034 004000 @E 001036 004000 @E 001040 004000 @E 001042 177773 @E 001044 177777 I replace the 000000 at 000000 and get all zeros. So I appear to have two problems: 1) Depositing any value is echoed 000020 later. 2) Setting D10 in location 000000 results in D10 set in all the locations I have few spares for this machine. Lots of spares for my 11/34 (which I will want to test at some point soon), but this box (BA11-L) has a DD11DK not a DD11-PK, so I can't just upgrade in place. Does this sound like a dodgy CPU, dodgy RAM or both? I have this minimally loaded... M7263 PDP-11/04 processor M7847 16K MOS RAM (half loaded) M9312 with console ROM and papertape boot ROM (I have more ROMs available) M7856 - DL11-W strapped to defaults as a console/RTC many dual-height grant cards M9302 terminator UA-11 debugging board Oh... and I see while typing that it just started halting immediately after reset... so something just broke while it was powered on and running the console ODT. :-( I guess I'm back to low-level hardware debugging again. But in the meantime, any CPU/RAM symptom suggestions? I have the prints. I'm just looking for any "oh, yeah! That happened to me!" with "...and I fixed it by testing X and replacing the bad ones". All this so I can make a test bed for my M9313 boards and get them working again to fix the DWBUA on my VAX 8300... -ethan