200 Watt Modified PC Power Supply 13. DO NOT TRY TO DO THIS MOD ! IF YOU Psu ripple NOT AWARE OF THE SHOCK RISK ! I got two old PC powersupplies for free, to be used for this test.
They are named DTK Computer model PTP-2008. OFF switch is removed and bypassed. Cut: white, orange, blue, and yellow wires as close as possible to the pcb. Cut: all plugs away in the other end of the black and red wires, parallel all red and black wires.
Mount solderpins in the holes for R26, R61 and Fan connection. This is a fast part-drawn schematic that only covers what I wanted to know. 5 K Ohm at the solderpins at R26. Mount 15 V Zener and 100 Ohm in series in the ZD1 holes. Orange wire connects unused cap to the new 13. 12 volt output vindings are connected to the high current double diode.
The fan is reverse mounted so that it will blow cold air into the heatsinks and transformer. If the temperature goes further up, the fan will rotate faster. Mount potentiometer 47 K at R61 solderpoints. Output ripple is under 5mV pp at 20 Amp. I have tested it with my HF VHF and UHF rig, and could not hear any more noise than usual.