Samsung PN42c430 dim picture

[happbear]

I can't adjust the Va and Vs voltages to spec. Turning the pots doesnt change the voltage neither higher nor lower. The spec voltage for Vs should be 210 but is 160, the Va voltage is 46 but should be 54.Any ideas anyone?

[tom66]

Re: Samsung PN42c430 dim picture

Most common this is actually the X-main (on Samsung at least), not the Vs/Va. Check your meter battery is good just in case this is the problem.

[gilly1984]

Re: Samsung PN42c430 dim picture

You prob no more than i do but are you turning the correct pots? I remember tom66 commenting on one and it had pots for va/vs and a couple of other for something else. I forget now though.

[happbear]

Re: Samsung PN42c430 dim picture

My meter batteries are new. The measurements were taken at the post Va and Vs on the main power board.

[selldoor]

Re: Samsung PN42c430 dim picture

What is that green cap bottom left corner of the board with the pots on.
Often the diameter is relative to the size of the circle on the board.
Is it an original cap? has this board been worked before - do you know the history
What are the two caps bottom right.

[tom66]

Re: Samsung PN42c430 dim picture

Does Vs rise when the Y-main is disconnected?

[happbear]

Re: Samsung PN42c430 dim picture

What is that green cap bottom left corner of the board with the pots on.
Often the diameter is relative to the size of the circle on the board.
Is it an original cap? has this board been worked before - do you know the history
What are the two caps bottom right.

Dont know the history, all looks original, checked replacement boards on ebay and the bords look identical to mine.

[happbear]

Re: Samsung PN42c430 dim picture

Does Vs rise when the Y-main is disconnected?

Vs drops to almost 0 when Y-main is disconnected

[tom66]

Re: Samsung PN42c430 dim picture

It should stay up for a few seconds if the TV turns off; where are you testing it, on the PSU?

[happbear]

Re: Samsung PN42c430 dim picture

All measurements are taken with a digital meter connected to chassis ground and Vs post.

Initial measurement 28mV

Energizing the PSU - 173V dropping to and stabilizing around 10V.

Power up the panel - 173V dropping to and stabilizing around 155V.

All this with the Y sus cable connected.

Now, you want me to disconnect the Y sus cable? At the PSU or at the Y sus board?

[tom66]

Re: Samsung PN42c430 dim picture

Disconnect at the PSU. If the Vs rises to the correct level, then it indicates an issue with the power supply (being unable to supply the power demanded.)

Have you also tried with a fully white screen to see if Vs drops off even more?

[happbear]

Re: Samsung PN42c430 dim picture

Ok disconnected

Energized the PSU - meter spikes to 193V emits three peeps while briefly displaying 1000V and then dropps rapidly to 0V aprox.

[happbear]

Re: Samsung PN42c430 dim picture

Ok disconnected

Energized the PSU - meter spikes to 193V emits three peeps while briefly displaying 1000V and then dropps rapidly to 0V aprox.

What do you mean by white screen?

[tom66]

Re: Samsung PN42c430 dim picture

Try connecting it to your computer and display a mostly white screen. This draws the most power.

This doesn't appear to be as such an adjustment problem, as it can go higher with no Y-main. I suspect that marked blue capacitor.

[happbear]

Re: Samsung PN42c430 dim picture

Try connecting it to your computer and display a mostly white screen. This draws the most power.

This doesn't appear to be as such an adjustment problem, as it can go higher with no Y-main. I suspect that marked blue capacitor.

Thanks Tom, I had to make room for the Xmas festivities and remove the tv of the kitchen table. I will look at it again in the new yearr. Thanks for your help and happy Holidays