Samsung PS51F4500

[satinser]

Customer reported sound with no picture.
Suspected from description of fault Ysus display board at fault.
With this model buffer chips built in to Ysus.
Xsus built into power board.
Mainboard with built in logik.
Total number of board therefore been kept down to 3.

All voltages test as correct on panel sticker but absolutely no picture or brightness from the screen or flash of screen when first switched on.
There is a sound however coming from behind the screen i can liken it to the noise some CRT tvs would produce when displaying a high contrast scene. The mainboard has green led flashing 1blink then 3 seconds off and repeating. Does anybody know whether this is the sign of normal operation as i have no service manual?
Because all voltages are reading good but still no screen activity of any kind thoroughly checked the screen for damage or any damaged burnt pixels.
There is small chip about the size of a pinhead on the screen barely discernible its difficult to see whether this has compromised the seal of front glass layer of screen.
Its difficult to believe but could this be the reason?
I dont have the service manual and neither can i find one from usual sources.
Any advice from anybody in the know appreciated.

[R_J]

Re: Samsung PS51F4500

I have seen cracks in a plasma screen that still worked and I have seen screens with a chip that did not work, If the gas escaped, it is done. If you feed video to the tv does the sound seem to come from the whole panel and does it sem to change with the video signal? if it does I would suspect the panel. You could also scope the signal going to the buffers and the panel. (10x probe as the signal is large)

[satinser]

Re: Samsung PS51F4500

Many thanks RJ. Your thoughts and comments very much appreciated.
Using EMR Diagnostika meter it clearly indicates normal energising of Ysus and Xsus section of power board. The ribbon connectors from both Ysus and xsus are also energised to panel. Despite all this the screen shows absolutely no illumination or activity whatsoever so looking increasingly like loss of gas from pin hole chip has occurred.
Over the weekend I will connect a working video feed as youve suggested and feedback the results here.

[satinser]

Re: Samsung PS51F4500

I can confirm that when fed video from set top box to HDMI port audio is as present as always but loud vibrating crackle noise is coming from the front of the screen. Its difficult to pinpoint in which area the noise is coming from. It does indeed alter in intensity and pitch in relation to video levels of input.
I guess this confirms Panel failure and thanks once again RJ for your reply and suggestions.