![Cover Removed Cover Removed](http://www.experimental-engineering.co.uk/wp-content/uploads/2011/01/GEDC0597-300x225.jpg)
Here is a cheapo 500W rated ATX PSU that has totally borked itself, probably due to the unit NOT actually being capable of 500W. All 3 of the switching transistors were shorted, causing the ensuing carnage:
![AC Input AC Input](http://www.experimental-engineering.co.uk/wp-content/uploads/2011/01/GEDC0600-300x225.jpg)
Here is the AC input to the PCB. Note the vapourised element inside the input fuse on the left. There is no PFC/filtering built into this supply, being as cheap as it is links have been installed in place of the RFI chokes.
![Input Side Input Side](http://www.experimental-engineering.co.uk/wp-content/uploads/2011/01/GEDC0601-300x225.jpg)
Main filter capacitors & bridge rectifier diodes. PCB shows signs of excessive heating.
![Filter Caps Removed Filter Caps Removed](http://www.experimental-engineering.co.uk/wp-content/uploads/2011/01/GEDC0602-300x225.jpg)
Filter capacitors have been removed from the PCB here, showing some cooked components. Resistor & diode next to the heatsink are the in the biasing network for the main switching transistors.
![Heatsinks Removed Heatsinks Removed](http://www.experimental-engineering.co.uk/wp-content/uploads/2011/01/GEDC0606-300x225.jpg)
Heatsink has been removed, note the remaining pin from one of the switching transistors still attached to the PCB & not the transistor 🙂
![Transformers Transformers](http://www.experimental-engineering.co.uk/wp-content/uploads/2011/01/GEDC0605-300x225.jpg)
Output side of the PSU, with heatsink removed. Main transformer on the right, transformers centre & left are the 5vSB transformer & feedback transformer.
![Output Side Output Side](http://www.experimental-engineering.co.uk/wp-content/uploads/2011/01/GEDC0599-300x225.jpg)
Output side of the unit, filter capacitors, choke & rectifier diodes are visible here attached to their heatsink.
![Comparator Comparator](http://www.experimental-engineering.co.uk/wp-content/uploads/2011/01/GEDC0610-300x225.jpg)
Comparator IC that deals with regulation of the outputs & overvoltage protection.