For search engines and repair techs using OCR, here is the critical verified schematic data for the Wannien 101v0. (Copy this to a text file or KiCad).
Primary Side (Hot):
Secondary Side (Cold):
This is the brains of the switching pre-regulator. On the 101V0, it is usually located on a small vertical daughterboard. wannien 101v0 power supply schematic verified
Why this matters: If your supply is making a squealing noise, the TL494’s compensation network might be failing. Check the ceramic capacitor (C_T) for cracks.
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.
The Wannien 101V0 uses an LM324 quad op-amp to manage the two operating modes: Constant Voltage (CV) and Constant Current (CC). For search engines and repair techs using OCR,
Verified Critical Component: The shunt resistor is not 0.05Ω as seen in other clones. It is 0.1Ω, 5W, wirewound. If your ammeter reads double the actual current, someone installed the wrong shunt.
| Symptom | Likely failure (from schematic) | Test point | |-----------------------------|-----------------------------------------------------|------------------------------------| | No output, fuse intact | Startup resistor open, or IC1 dead | Voltage at IC1 pin 7 (should rise) | | Output voltage jumps / unstable | TL431 divider resistors drifted, optocoupler weak | Output divider junction (~2.5V) | | Output low (e.g., 8V instead of 12V) | Secondary filter capacitor high ESR, or feedback loop broken | Check C2, C3 with ESR meter | | Squealing noise + no output | Transformer shorted turns, or output short circuit | Resistance across secondary winding | | Blows fuse immediately | Bridge rectifier shorted, MOSFET shorted D‑S, bulk capacitor shorted | Diode test on D1–D4, MOSFET |
Having the verified schematic allows you to trace the exact signal path and measure voltages against expected values. Secondary Side (Cold): This is the brains of
The Wannien 101V0 is not a pure linear supply (which would be heavy and inefficient) nor a pure switching supply (which can be noisy). Instead, it uses a hybrid topology:
This design allows the unit to be lightweight while still delivering the low-noise output required for sensitive audio or RF circuits.