Wannien 101v0 Power Supply | Schematic Verified

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.

Look at RCD snubber across the primary winding:

If your board has a 10k resistor here, it is a fake revision. Replace with 47k to prevent the MOSFET from blowing under load. wannien 101v0 power supply schematic verified

Pre-regulation / heat distribution

5 V rail

3.3 V rail

Reset/brown-out and supervision

Miscellaneous rails and references

Root Cause: Failed startup capacitor (C8 on aux winding). Verified value: C8 = 50V 47µF (Low ESR, 105°C). Fix: Replace with Panasonic FC or Nichicon PW series. The fake schematics wrongly call for 100µF, which delays VCC rise time and causes the controller to hiccup. The TL494’s output signal is too weak to

Primary conversion

Secondary/regulation

Supervisory and sequencing

Protection and filtering on outputs