Westinghouse VR-4625 wont turn on

[budm]

Re: Westinghouse VR-4625 wont turn on

That is the MOSFET for the PFC Voltage booster, the IC driving is probably bad/damaged, plus may have also burn open the two Source pin of MOSFET resistors connected in parallel to the primary ground.
See if you do have about 360~400VDC on the two legs of the main filter cap (450VDC), the 24V power supply will not work if the boosted voltage is not present.

[jesselyons2002]

Re: Westinghouse VR-4625 wont turn on

If thats the big capacitor on the board. Then no it only has 12v ac

[Agent24]

Re: Westinghouse VR-4625 wont turn on

Your diode bridge is probably shorted - main filter cap shouldn't have AC on it at all.

But 12v would be enough to make a 5v standby circuit work...

[budm]

Re: Westinghouse VR-4625 wont turn on

You need to put meter in DC to measure the Boosted voltage on that main filter cap.

[jesselyons2002]

Re: Westinghouse VR-4625 wont turn on

Your diode bridge is probably shorted - main filter cap shouldn't have AC on it at all.

But 12v would be enough to make a 5v standby circuit work...

Where would the diode bridge be ???

[tw2005]

Re: Westinghouse VR-4625 wont turn on

[budm]

Re: Westinghouse VR-4625 wont turn on

What do you get in DC V on your meter?

[Agent24]

Re: Westinghouse VR-4625 wont turn on

Sorry, disregard my previous statement about the bridge being shorted, that was meant to be posted in a different thread!

[jesselyons2002]

Re: Westinghouse VR-4625 wont turn on

What do you get in DC V on your meter?

Well time to check

[jesselyons2002]

Re: Westinghouse VR-4625 wont turn on

18+ volts of dc on the main cap The big cap on the board

[jesselyons2002]

Re: Westinghouse VR-4625 wont turn on

Throw out some more info

[budm]

Re: Westinghouse VR-4625 wont turn on

Hmm, main voltage is only 18V instead of 160~170VDC on the TWO LEGS of that main filter cap. What AC voltage do you get at the two inner legs of the bridge rectifier as shown on post 26.

[budm]

Re: Westinghouse VR-4625 wont turn on

Can I get the straight shot pictures of the bottom side of the board? The other picture is tilted so it is hard for me to trace out the connections.
Never mind, I found good pictures on shopjimmy:
http://www.shopjimmy.com/westinghous...-version-1.htm

Can you remove the two screws on the heat sink so I can see what is under the heat sink?

[jesselyons2002]

Re: Westinghouse VR-4625 wont turn on

Here's the pic. and got 58 ac and 60 ac on the bridge rectifier.

[budm]

Re: Westinghouse VR-4625 wont turn on

OK, thanks for the pictures, I will spend some times tracing out the circuits.

[jesselyons2002]

Re: Westinghouse VR-4625 wont turn on

Thanks. If it helps out.

[jesselyons2002]

Re: Westinghouse VR-4625 wont turn on

Anything you need help with that I can do

[budm]

Re: Westinghouse VR-4625 wont turn on

OK, check the PFC diode, pfc inductor (should have low resistance between those two pins), TH1.

[jesselyons2002]

Re: Westinghouse VR-4625 wont turn on

Pfc read good, pfc inductor .2 ohms across the leads shown in the pic and th1 3ohms

[jesselyons2002]

Re: Westinghouse VR-4625 wont turn on

This is with the board out of the tv and nothing connected