Philips 32PFL7403D/12 - Shorted mosfet -Delta DPS-182C Ppower supply

[sententia]

Hello everyone!

I am trying to repair this power supply and i seem to be kind of stuck...

Mosfet Q603 was shorted, which also took out R634 ....

The small main cap C910 (33uf) had leaked and was off...

I have replaced both mosfets, the capacitor and the resistor and now have standby power but as soon as the relay clicks to switch on the TV i get 6 blink error led.... according to service manual its the 5V 12V supply error....

I cannot find any other damaged parts, does anyone have any suggestions or can point to a direction please?

Thank you!

[sententia]

Re: Philips 32PFL7403D/12 - Shorted mosfet -Delta DPS-182C Ppower supply

Anyone any input?

[dick_barton]

Re: Philips 32PFL7403D/12 - Shorted mosfet -Delta DPS-182C Ppower supply

If you disconnect the mainboard from the power supply and connect the 3.3V standby to PSON using a 1K resistor, does it bring up the 5V and 12V supply.

[sententia]

Re: Philips 32PFL7403D/12 - Shorted mosfet -Delta DPS-182C Ppower supply

PSON does seem to turn on the power supply (relay does not click)...

There is no voltage on the 12v pins.

on the other terminal there is also an ON/OFF pin if that has something to do...

Thanks for the input!

[dick_barton]

Re: Philips 32PFL7403D/12 - Shorted mosfet -Delta DPS-182C Ppower supply

ON/OFF is possibly the Tcon voltage.
There's a fusable resistor above D603 in the schematic. Have you checked it has not blown?
Is the 24V also missing?

Edit
What is the base/emitter/collector voltage on Q900

[sententia]

Re: Philips 32PFL7403D/12 - Shorted mosfet -Delta DPS-182C Ppower supply

That resistor R634 was blown when the mosfet shorted...

It was replaced and is still good...

No output on the 24V either (it only connects to the inverter)

I do get 3.3 from 3.3VSB ...

:EDIT: Ok PSON needs to be pulled to Ground for the supply to switch on (the relay), but still no output except the 3.3VSB

[dick_barton]

Re: Philips 32PFL7403D/12 - Shorted mosfet -Delta DPS-182C Ppower supply

Can you give the voltage on the 3 legs of Q900

[sententia]

Re: Philips 32PFL7403D/12 - Shorted mosfet -Delta DPS-182C Ppower supply

I was trying to desolder IC901 that was corroded and i may have shorted it due to overheating (probably).... It just wouldn't come off...

Either way the was a bit of smoke upon power on and got some nice fireworks after a min

I will need to take care of that before any further testing...

Thank you for the help!