usp440m-42lp psu

[joehezzer]

Re: usp440m-42lp psu

Ok, keep us posted about your findings. There is not much left to check.

In the meantime I will spend another evening on my board

will do

[paulstef]

Re: usp440m-42lp psu

Ok, keep us posted about your findings. There is not much left to check.

In the meantime I will spend another evening on my board

[joehezzer]

Re: usp440m-42lp psu

There is also an EMI filter directly connected to the AC inlet of the TV. Maybe it's faulty. You could measure the output voltage at its terminals.

i have not tested it yet but it does smell a little

[paulstef]

Re: usp440m-42lp psu

ok. good luck. Shouldn't be hard.

[joehezzer]

Re: usp440m-42lp psu

gonna have to give it a break tonite, will go over these bits tomorrow.

[joehezzer]

Re: usp440m-42lp psu

There is also an EMI filter directly connected to the AC inlet of the TV. Maybe it's faulty. You could measure the output voltage at its terminals.

yeah just looking at that now

[paulstef]

Re: usp440m-42lp psu

There is also an EMI filter directly connected to the AC inlet of the TV. Maybe it's faulty. You could measure the output voltage at its terminals.

[joehezzer]

Re: usp440m-42lp psu

That's very strange. Is your multimeter working? What if you measure the AC directly at the wall outlet?

well the extension lead is working as i have just tried my belt sander on it. just going to have a look at a faulty rocker switch and the bit where the kettle lead goes in

[paulstef]

Re: usp440m-42lp psu

That's very strange. Is your multimeter working? What if you measure the AC directly at the wall outlet?

[paulstef]

Re: usp440m-42lp psu

Well, then the problem is somewhere else. I don't have the TV in front of me, just the board. Check the connector/cable etc.

[joehezzer]

Re: usp440m-42lp psu

Nothing. Extension lead is fine

[paulstef]

Re: usp440m-42lp psu

Check input voltage directly at the connector. Sure it's there?

[joehezzer]

Re: usp440m-42lp psu

i did a continuity test on it, i took the fuse out of its holder

[paulstef]

Re: usp440m-42lp psu

????

Are you sure the fuse is ok?

You measure AC, right?

[joehezzer]

Re: usp440m-42lp psu

Perfect. What's the voltage at the points indicated in the picture?

Bouncing around 00.3 to 00.7 that looks a bit suss

[paulstef]

Re: usp440m-42lp psu

Perfect. What's the voltage at the points indicated in the picture?

[joehezzer]

Re: usp440m-42lp psu

If you don't have DC voltage between pin "+" and "-" of the bridge rectifier then it is either faulty or there is no AC coming in.

Measure AC between the two inner pins of the bridge rectifier. If there is none then follow the two traces back.

What's the voltage on TNR 102? The green round component right beside R105 R106?

voltage on TNR 102 00.3v

[paulstef]

Re: usp440m-42lp psu

Check the resistors R105 R106. Mine are 20R each. Yours could be different since we have 120VAC here.

[paulstef]

Re: usp440m-42lp psu

The blue relay only bridges the two white resistors when you turn on the TV. It limits the inrush current when the two big caps are discharged and you plug the TV in.

Normally AC goes through the two resistors. There should DC on the big caps even when the relay is OFF.

[paulstef]

Re: usp440m-42lp psu

If you don't have DC voltage between pin "+" and "-" of the bridge rectifier then it is either faulty or there is no AC coming in.

Measure AC between the two inner pins of the bridge rectifier. If there is none then follow the two traces back.

What's the voltage on TNR 102? The green round component right beside R105 R106?