Primary conversion
Secondary/regulation
Supervisory and sequencing
Protection and filtering on outputs
Do not trust any schematic until you confirm these points:
The transformer (T1) is hardest to fake. On the schematic:
Measure continuity on your PCB:
If the schematic shows auxiliary winding connected to pin 5 of IC1, but you measure it connected to pin 7 – the schematic has swapped pins. wannien 101v0 power supply schematic verified
If no reliable schematic exists, create your own verified copy:
The schematic indicated a Y-capacitor between primary ground and secondary ground. Physical inspection confirmed a 2.2 nF / 250V Y1 capacitor present, critical for EMI reduction and safety isolation.
Check: RV1 (Varistor) and BD1 (Bridge rectifier). In verified schematic: RV1 is a 14D471K. If the input voltage spiked >470V, RV1 shorts to protect. Remove RV1 temporarily to test. If BD1 is cracked, replace with KBP310. Primary conversion
The TL494’s output signal is too weak to drive the main transformer directly. The 101V0 uses an intermediate driver transistor (often a TIP122 Darlington) to boost the current.
Verified Failure Mode: If the 2N3055 fails shorted (collector to emitter), you will get full unregulated voltage at the output terminals regardless of the potentiometer setting. This is dangerous for connected devices. Immediately replace the 2N3055 with a genuine TIP35C or MJ15003 for better reliability.