Recently got this non working power supply. Replaced the 2N3773 x 4 transisters and all the electrolitics. Tested with a 12v headlamp and it seemed to work ok. Have not had any equipment connected to it but have turned power on with no load. there was a noise like a surge sound to which I assumed was the caps charging. Tonite thinking about connecting a load to it noticed that the voltage was low (10 volts on the meter) but volts dropped to zero when load was applied. Also noticed that no surge sound when switch turned on. Any suggestion to where I might look would be appreciated.