While a complete, downloadable schematic for the Wannien Model E88653 101V0
Uses a PWM controller IC and a power MOSFET (often attached to a large heat sink) to chop the DC into high-frequency pulses for the transformer. Secondary Rectification & Filtering: wannien 101v0 power supply schematic exclusive
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AC LIVE ----[ FUSE ]----[ BRIDGE ]----+----[ 400V CAP ]----+------+ | | | | | | AC NEUTRAL -----------------------------+ | | | | [Snubber] [Transformer Primary] | | | | +-------------------------------------------------------+ | | | | +------------+ | +---| DRAIN | | | | | HV Bus ---| VDD PWM |<---[ Aux Winding ]-------(Feedback)-------+--+ | | +---| VCC GND |---+---[ Rsense ]--- GND | +------------+ | | | [Startup R] | | | +--------------------+ Control and Monitoring: Uses a PWM controller IC
: "No power" or "no display" symptoms are often traced to aging or blown capacitors. Testing these with a multimeter is the first step in a standard repair. Switching Transistors
While many guessed it used a UC3842, the exclusive schematic reveals a (identical to TL494). This is a pulse-width modulation controller running in push-pull mode.