Samsung Plasma -no picture/sound -just clicks

[Cornboats]

Samsung 42SD 5SD plasma 42"

No picture or sound. Turn it on, clicks and the neon flashes 5 times and then goes off. re-cycles until you turn off at mains.

It did have picture and sound but had vertical lines and occasional horizontal dashes. I never got to the bottom of the first fault before the second one took over.

I've disconnected Z-sus and Y-sus boards 1 at a time but no difference.

Va and Vs voltages as per label.

Where do I go from here?
Anyone offer any adivice-it would be welcome.

[randtek]

Re: Samsung Plasma -no picture/sound -just clicks

Here's a trick that may help you. It will immediately tell you if you have a main board problem, or a panel drive board failure.

1) Unplug the TV from AC.
2) Disconnect the power supply cable going to the main board at the main board end.
3) Look at the legend on the power supply board to determine which pin is PS-ON, usually pin 1. Stick a wire in this pin of the connector cable you disconnected from the main board, and short it to ground.
4)Disconnect the LVDS cable going from the main to the Digital board.
5) On the digital board find 4 test point pins sticking up from the board in a square pattern, about 1/8" across. Short these pins together.
6) Plug the unit in to AC.

This process will generate test patterns from the digital board. If you see the test patterns begin to cycle on the screen, you know everything is working properly except your main board. If you do not see the test patterns, you have an issue in the panel drive circuitry.

[noahc72]

Re: Samsung Plasma -no picture/sound -just clicks

I had the same problem with my Samsung PN58. Changing the main board fixed the cycling problem on mine, although now I have a different problem.

Haven't tried this test pattern trick yet, but I will try it later today.

[Cornboats]

Re: Samsung Plasma -no picture/sound -just clicks

Thanks for your test tip.

I'm a bit confused so I'm checking as I don't want to blow the boards up.

The main board your refering to is referred to in Samsung manual as Video board.


PS-ON is pin no 7 on CN810. This block goes from main smps to digital board not the video board.

So I'm not disconnecting any cables from the video board only the digital board and the the LVDS which connects the video board to the digital board?


On the digital board

theres a strip of 7 pins in a row,
6 pins in 3 doubles ( 2 pairs are jumpered)
4 pins in 2 doubles (1 pair is jumpered)

The last on above is the one I want I reckon.
As pins 1 and 2 are already jumpered I'll just jumper 3-4.