Hi! As I'm preparing to setup my old hardware, I fetched two VAXstations (4000/90 and /96) from storage and cleaned one of them throughoutly.
Then I gave power (to both of them), but both won't really start: all 8 diag LEDs are on (--> power available but CPU didn't start executing instructions.) I took the PSU (from the cleaned /90), a DEC H7819-AA, and measured it. Unfortunately I didn't find pinouts or schematics at a first search. The plate states that there should be 3.3V, 5V, 12V, -12V and -9V. I found most of that: +------------------------------------------------------------------+ | o | | DEC H7819-AA PSU 10 +---+ 1 | | (view at the bottom side) | | | | | | | | | | | | 18 +---+ 9 | | o | | +-------+ +-------+ | | | Fan | | Fan | | +----------------+-------+----+-------+----------------------------+ With above pin numbering, this is what I could find / measure / deduce: 3V3 brown 10 1 blue 12V 3V3 brown 11 2 black GND GND black 12 3 red 5V GND black 13 4 red 5V GND black 14 5 black GND 5V red 15 6 black GND 5V red 16 7 white -12V 5V red 17 8 blue (0.78V) (4.91V) lilac 18 9 brown (-1.65V) Most values look plausible, except those three in parentheses. At least one of them should probably be -9V wrt. GND I guess, but that's totally absent. And what's the other two? (If I got the colors wrong: Please forgive, I'm red-green blind.) That could be some "power-okay" indicator, or external switch-off? Maybe anybody has faced these issues and can point me to some docs or "well known to be failing" capacitors? I'd be quite grateful for any hints! :) ...and hope that maybe the above drawing/measurements will be helpful for anybody else later on. Thanks, Jan-Benedict --