Hi all, I just got done fixing a piece of apparatus that was returned to us. The thing was trashed, (all sorts of blown components) and I've been trying to figure out what happened. Perhaps what I found weirdest is a power monitor LED. This sits across the +/-15 V rails, with a 12V zener and 5 k ohm resistor in series. (the zener stops it from turning on if one of the rails fails.) It just barley put out any light.... trashed. It can take 30 mA forward so >~150 V for too much current. And in reverse it doesn't break down till -80 V. (I just tested it... it shows a photo response too, but don't distract me.)
So I was in contact with the school that was using this.. checking return address, and I asked if they wanted a new brick on the rope. (Because they hadn't returned theirs with the unit.) It was just then that I learned that the brick on the rope had failed!! And they had purchased a new one from the vendor (astrodyne)
So my current theory is that the brick on the rope failed (somehow) and blew 120 Vac through my circuit.. with devastating results. Any idea how I can test this theory.. how do I blow up a brick on a rope? (Astrodyne Mod num. SPU45-210) +15 V @ +2A / -15V @ -1A.
Thanks George H. (maybe I should contact astrodyne.)