On the output side, high-speed convert the pulses back to steady DC.
Often uses an 8-pin IC (like the LD75xx or SG68xx series).
Understanding the is essential for technicians repairing modern LCD monitors and small electronics. While "exclusive" schematics are often guarded by manufacturers, most Wannien boards follow a standardized switch-mode power supply (SMPS) topology.
If your board is dead or malfunctioning, check these components in order:
A high-voltage transistor that chops the DC voltage into high-frequency pulses.
The high-frequency pulses pass through the transformer. This step steps down the voltage while providing a safety barrier between the "hot" AC side and the "cold" DC output side. 4. Secondary Rectification & Filtering
Metal Oxide Varistor (MOV), X-capacitors, and Common Mode Chokes. Goal: Convert AC to a "dirty" DC and filter out line noise. 2. The Primary Switching Stage This is the "heart" of the power supply.
Get a step-by-step for this specific board?
High-value resistors (around 100kΩ) near the PWM IC. If they go open-circuit, the board won't "start."