Samsung PN42B450B1D Bad Panel?

[alfredomfr1]

Hi
I need advise about this image, should be a bad panel?.
The TV do not have sound.

[tom66]

Re: Samsung PN42B450B1D Bad Panel?

Unlikely - looks more like Y-buffer fault, or control board issue.

[alfredomfr1]

Re: Samsung PN42B450B1D Bad Panel?

How can I troubleshot this problem?

[tom66]

Re: Samsung PN42B450B1D Bad Panel?

It's a tricky one; do you have a digital multimeter available? What about an oscilloscope? Take some pictures of the boards in the set.

[alfredomfr1]

Re: Samsung PN42B450B1D Bad Panel?

I have a digital multimeter and the service manual

[DoubleDratt88]

Re: Samsung PN42B450B1D Bad Panel?

There should be some info on this in the service manual, but basically on the logic main board in the 5th image, there is a group of 4 pins. By placing a jumper on pins 3-4 and disconnecting the ribbon between the logic and main boards then powering on the set you can access a built in self test to try and isolate the main board as the problem.

Edit: see the 2nd post from tom in this link- https://www.badcaps.net/forum/showthread.php?t=26790

If the test results in full screen colors and patterns then the problem is your main board - and the logic, y-main and panel are ok.
If the test fails then I'm afraid I'm not sure. But you shouldn't be any worse off than where you are now by trying this.

In any case, do a quick search and check of the manual before attempting this. If your set powers on ok from the power button then you can skip the parts about jumping the PS_ON signal on the power supply and just disconnect the ribbon between the logic and main boards and use the power button on the remote.

Since you have no sound either and the speakers appear to be connected directly to the main board, i would guess the main board.
- but tom knows far more about these things than i do and has helped alot of folks around the world have success fixing their tv, so i would probably listen to him instead of myself! :-)

I'm a rookie but am yet to see a y-main take out the sound with it even on models that do run sound via the y-main. Not saying it can't happen though.

For a new main board I'd keep an eye on wePay or SJ, and make sure ALL the numbers match, or cracked screen tv of exactly the same model to salvage from. Provided you don't overpay or damage anything then even if that's not the problem you should be able to re-list it for near enough to the same price you paid and not get left out of pocket too much for trying.

Just my 2c.
DD.

[alfredomfr1]

Re: Samsung PN42B450B1D Bad Panel?

This was the self test result: see the picture

[tom66]

Re: Samsung PN42B450B1D Bad Panel?

I would replace the control/logic board (the one with the 4 pins) and see what it looks like when you do that. It is very hard to be sure but I think it is driving the plasma panel wrong and causing this issue.

[DoubleDratt88]

Re: Samsung PN42B450B1D Bad Panel?

Strange result.
I'm not sure sorry, but it was worth a try :-)

Edit: I was too slow!

Sorry I can't be of more help,
DD.