ATX PSU shorted blow fuse

[ITSYSTEMSALBANIA]

Hi all

I have a cheap Winstar 450w atx psu when i opened it i see blown fuse i started measuring on primary side and found 2 diodes on bridge rectifier open and a n-channel mosfet CS2N60F shorted i replaced all this components and power om the psu the fuse blow and the 2 diodes shorted again i measured the mosfet that i replaced from gate to source and i get 85 ohm resistance.Please help me to troubleshoot this psu.

[CapLeaker]

Re: ATX PSU shorted blow fuse

Post good pictures from the top and the bottom of your power supply.
Once the mosfet blows, usually there are bad components on the gate drive circuit of the mosfet.

[stj]

Re: ATX PSU shorted blow fuse

fet is probably locked on because of a blown drive circuit.

[ITSYSTEMSALBANIA]

Re: ATX PSU shorted blow fuse

Hi thank you for your replies circled in red are the components that i replaced the primary caps are 200v 470uF the mains voltage in my contry is 220v is this a problem and here and the photos.

[ITSYSTEMSALBANIA]

Re: ATX PSU shorted blow fuse

Looking on the primary side i see a blown C945 transistor and a open resistor.

[ITSYSTEMSALBANIA]

Re: ATX PSU shorted blow fuse

Replaced the C945 transistor and resistor and the psu is working.

[ep9es]

Re: ATX PSU shorted blow fuse





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[ben7]

Re: ATX PSU shorted blow fuse

You should also replace that resistor that looks burnt on the secondary (output ... low voltage) side, it's right next to a capacitor.

Also replace the output electrolytic capacitors ... they look to be cheap ones, they will fail sooner.