**Cougar GEC 650 power supply repair.**

So, here’s the next power supply—GEC 650. As usual, we connect it to the TMP and power it on. The lamp doesn’t light up, meaning either a blown fuse or a fully discharged capacitor. Now, we’ll open the unit to check the issue. First, we’ll disconnect the fan connector. I don’t see any swollen capacitors, so let’s check the fuse. It’s open. I don’t see a varistor failure, so likely something more serious—like burned power MOSFETs in the PFC stage. The design looks solid: a full input filter, a diode bridge on a heatsink. There’s only one PFC MOSFET here, but space exists for a second. This is a 650W unit—more powerful models have a second MOSFET. The main converter has four transistors. A 12V synchronous rectifier boosts efficiency. Plus, a DC-DC converter for 5V and 3.3V outputs. The design follows modern standards. Now, let’s pull the PCB—no visible burns.