Samsung PN50B450B1D no picture

[Hamie]

Re: Samsung PN50B450B1D no picture

Power supply end.

[jason424]

Re: Samsung PN50B450B1D no picture

Here's pics of each end

[Hamie]

Re: Samsung PN50B450B1D no picture

OK so vs-on is labeled there. Does it spike when you initially turn on the set?

[jason424]

Re: Samsung PN50B450B1D no picture

Yes, it went up to 3.2

[Hamie]

Re: Samsung PN50B450B1D no picture

so mainboard is OK.

The power supply appear to be your culprit then.

If you're going to try to repair it your fault is 'most likely' in the top section of the board as it appears to be an issue with VS.

[jason424]

Re: Samsung PN50B450B1D no picture

OK, thanks again for the walk through troubleshooting Hamie

[jason424]

Re: Samsung PN50B450B1D no picture

So I received a replacement power board and it's still exhibiting the same behavior. I did get the original control board back and put that back in too.
The new power board came with the corner broken off from the postal service being too rough on it. This is the second board as the first one came pretty bad. It doesn't look like any tracers or circuitry were damaged on the corner. I'm not sure if I should just send this one back too and start over troubleshooting with the orig ctrl board in?

[Hamie]

Re: Samsung PN50B450B1D no picture

With the power supply jumped on you should get permanent vs and va voltages. They shouldn't flicker or bounce around.

Have nothing connected to the power supply. And try and jump it on. VS should be around 200v and VA around 60.

If you're unable to get stable voltages from your power supply(s) there's no point testing elsewhere as these voltages will also be off.

[jason424]

Re: Samsung PN50B450B1D no picture

OK, I jumped the PS ON and Standby as you had stated in previous posts on this new board and I get 210 and 52 for VS and VA which are close to the 209 and 55 on the sticker. So I assume the new board is OK, at least as far as making power? So could it be the control board? It only blinks green when I first plug the set in to power, sound like a relay clicks on...led comes on...then relay click off....led goes out.

[Hamie]

Re: Samsung PN50B450B1D no picture

Probably not, you may have a short somewhere else.
With the y-sustain unplugged does the tv turn on?

[jason424]

Re: Samsung PN50B450B1D no picture

The TV always turned on (chime sound) and stayed on. But now with all cables to the YSUS unplugged and when I turn it on I get the green LED blinking on the control board.

[Hamie]

Re: Samsung PN50B450B1D no picture

In post 29# youve stated the power supply turns on then turns off?

[jason424]

Re: Samsung PN50B450B1D no picture

Sorry I was talking about the led on the control board. Now with the Ysus unplugged, the led on the control board stays on. It doesn't turn off with the second click sound (that sounds like a relay clicking). Hope that makes better sense

[jason424]

Re: Samsung PN50B450B1D no picture

So I assume there is an issue with the Y-sustain board...and possibly the buffer? Is there a way to test the buffer, and for that fact the Z-sustain to be sure I won't need to replace or repair those as well?

[jason424]

Re: Samsung PN50B450B1D no picture

Just getting back to this set. I sourced a replacement YSUS and still get the same behavior with the Control board LED going back off right away upon powering on the set. If the YSUS is unplugged the LED stays on (blinking on/off continiously).
Is there a way to test the buffer? Or should I just be looking for a replacement?
And could there be an issue with the ZSUS? Possible tests to do to rule out needing a replacement there as well?

Thank you,
Jason