LF: Microvax 3100 power supply technical information.

It's complex enough that I'd feel better going at it with a set of schematics. If nothing turns up I'll draw it out myself, but if someone has technical data it could save considerable time. Agreed completely - I guess I wasn't clear. I haven't done any debugging yet, just a brief characterization of the symptoms - I received it with the statement "it doesn't work on this supply, I think the 12v or something is dead, but it works on this one borrowed from another unit" - With a light bulb limiter and multimeter I did a quick verification on the rails and discovered that they were all present, and followed far enough to give the observations stated previously. Thats when I decided to see if technical data was available before digging much deeper. The problem with "just going at it" is that sometimes you make what seems like reasonable assumptions that one look at the schematic will tell you are completely wrong. The description of symptoms was just in case this is a common/known DEC supply failure mode. I too suspect a lack of regulation and crowbar trip, and yes in the absense of technical data, I'll probably "shotgun" the electrolitics in the hope that I'll get lucky. It is at least fortunate that the working board and the non-working board are VERY similar. Once I draw it out I may be able to do some comparitive debugging. They are open collector signals (or at least they appear to be). If no tech data surfaces, I'll spend some time with the scope and provide more detailed information sometime in the next week or so. Funny - I don't see any problem with "mains frequency" - I've seen household AC power referred to as "mains" many times. Dave -- dave06a (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Collector of vintage computing equipment: http://www.classiccmp.org/dunfield/index.html