Re: Awkward Power supplies.

[TQuiroz]

Hi Declan, Maybe this will give us some more clues: What kind of shorts and faults did you find? and where? Have you tried force feeding 24V to the second stage? (with a suitable current-limited DC source) How about replacing the +/-15V inputs with dummy loads?   -Tony   Declan wrote: I have the repair job on 3 dc/dc converters, worth a lot, but very awkward. They have a switched transformer feeding 3 further switched stages (+24VDC in , +/- 15V out, &aux supply). Some problem fed 24V back up a +15V line. I have removed all visible shorts and faults,  and still the input switched stage will not run, so the second 2 receive no power. I have 2 questions:     1. Why - what's it thinking? How does it know the outside supply     is/was buggered?     2. Any ideas on this thing in the middle of this pcb. It looks     like a pcb 'sandwich transformer', and has loads of connections     off the pins underneath. The black part in the middle is ferrite http://homepage.ntlworld.ie/e-tronic.genius/smpsucard.jpg