Chassis is a CTC169BTA. Checked power supply on pin 16 of switching IC controller, and the voltage is not stable - swinging from a few volts to about 15 volts. Managed to check the 15 volt standby test point (no voltage) when my test probe slipped. Now I definitely have a known bad part - switching transistor. Anyway, since I don't have a schematic, I tried to trace the 15 volt source back, but get lost. Should I be following this direction, or should I be checking the 5 volt standby? A schematic and or anyone's suggestions for next step much appreciated. Thanks group.