The pair of diodes in parallel and the relatively large output capacitor strongly suggest this is a multi-Amp supply (2-5A would be my guess). Its too bad that you don't have a bench supply available. My next step would be to substitute the bench supply for the internal 5V supply and slowly crank up the current limit to see what happens (and to see if anything gets hot). dwayne At 04:28 PM 9/5/2009, Carl Denk wrote: >Here's the schematic, excuse my chicken tracks, but thought quick to >keep thread alive was better than a fine looking drawing. There are >no regulators that I could find in the 5 volt area, just off the >transformer winding(s). The transformer primary seems to be a >switching off the 120 VAC, with a diode rectifier bridge, and then 2 >MOSFETS and on to the transformer. Next back to trying to measure >the ripple on the 5 volt, and try powering the video board off >another supply. I have some 100 ma fast acting fuses that I can try. >They are for the meters ma ranges. -- Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist