This component provides feedback from the output side to the input side, ensuring the voltage stays constant.

Look for "domed" or leaking electrolytic capacitors. These are the #1 cause of failure in SMPS boards.

A bridge rectifier converts AC to DC, which is then smoothed by a large electrolytic "bulk" capacitor.

If your device isn't powering on, follow these steps to diagnose the Wannien 101V0 board:

Works with the optocoupler to monitor output precision. 3. Verified Troubleshooting Steps

Usually mounted on a heatsink. Check for shorts between the Drain and Source pins.

The Wannien 101V0 typically operates as a . It takes a high-voltage AC input and converts it into stable DC output voltages (commonly 12V and 5V) to power the logic board and backlight of a display.

Measure the output pins. If you have 0V, check the startup resistor (usually a high-value resistor near the PWM IC) which provides the initial "kick" to start the switching process.

Test the main input fuse for continuity. If it's blown, check the bridge rectifier and MOSFET for shorts before replacing it.

A PWM (Pulse Width Modulation) controller chip drives a MOSFET to "switch" the DC voltage across a transformer at high frequencies.