IBM 5155 Power supply schematics or info

I traced out scheamtics of the PSUs in all my IBMs... How quickly do you need this? I am wondering if handing a copy to a friend at an HPCC meeting in a couple of weeks time would be soon enough. Yes, and the control chip is on the 'output' side of the PSU, the drive to the bases of the chopper transistors is transformer-coupled. There are 3 little daughterboards in there. One is an inrush limiter and contains a relay that shorts out a power resistor once the smoothing capacitors have charged. Another contains the overcurrent protection circuit, and, IIRC, a 12V regulator. The last contains the overvoltage protection circuit (the chips on that board are LM339 quad comparators). Waht I would do next is : Check you're getting about 350V DC across the mains smoothing capacitors (2 electrolytics in series) CHeck you're getting power to the 3524 (if not, troubleshoot the circuit round that little transformer you mentioned) Check that the 3524 is oscillating. -tony