Thermalltake Toughpower 550W PSU

[betwixt]

This PSU in one of my PC systems has died, I've bought a new one to keep me in business but the old one is in almost perfect condition so it seems a waste to throw it out when it could be repaired. I can't find a schematic and the thing is so cluttered it would take ages to trace the schematic, has anyone got a copy already?

I know there are different versions around, this one has a daughter board with a "CONTROL001" IC on it from CWT and an L4981 PFC controller from ST on the main board.

The incoming AC is being rectified and reaches the reservoir cap, the PFC circuitry is powered up and seems OK (the resistor in the snubber network across the control MOSFET was open circuit but that wouldn't stop it working and I've replaced it anyway). The 5V standby supply is fine. There seems to be a power transistor is series with the input side of the transformer which I assume is the power switch to turn the main PSU on, it has 350V on it but appears to have no bias on it so it isn't conducting, this obviously results in the zero output I'm seeing.

There are three opto-couplers between the primary and secondary sides, one is in the standby supply and is working OK, one of the others has 5V on both sides of the LED and the other 0V on both sides (they are not short circuit). One of these is probably the regulation feedback and the other the on/off control but what I need if anyone can help is how these are wired to the rest of the circuit. The voltages on them do not change when the green 'standby' wire on the main power output plug is grounded (it has 5V on it when not grounded).

Can anyone help with a schematic?

Brian.

 

[Electro nS]

why donot you post photos from inside the psu

 

[betwixt]

A photograph would not help, most of the components are burried under heatsinks and a mass of wiring. I was asking if anyone had already reverse engineered one and had a schematic I can work from. The design looks like it's from Sirfa and is the same or very similar to most 550W PSUs.

I've traced most of the schematic and I was correct about one of the opto-couplers being the 'on/off' control for the main SMPS but it seems to be driven by the "CONTROL001" IC which I'm guessing is some sort of comparator for each of the output voltages as it also produces the power-good signal to reset the motherboard. There must be a timer mechanism in it to allow the main PSU to start up before it can check the other voltages but I haven't traced all the circuit around it yet.

Brian.