Samsung PN51D7000 plasma TV: No display after loud "

[BACONputing]

I have a Samsung PN51D7000 plasma 3D television that was manufactured in October 2011 and purchased a couple months after that. It has worked without issue until recently I was watching TV one night and it made a loud "pop" or "snap" noise. The display turned off but the audio kept going.

The only devices I have connected to the TV are my HTPC (via HDMI) and a Wii (via composite dongle). Audio plays through the built-in speakers in either case.

Here are the symptoms I am experiencing:

• When I plug the TV in it "clicks" on (the same "click" as, when the TV worked properly, when it was already plugged in and I pressed the POWER button) and the red indicator above the bezel buttons flashes 6 times and then stays off.
• A green LED on the logic/main board flashes in the following pattern: 3 seconds on, 1 second off. When the TV was working properly and powered on, I think this LED was always on (I could see it through the grille on the back panel), but I never paid enough attention to it to say for sure.
• The display never turns on. There is no Samsung logo, no "Searching for input" screen, and pushing the MENU button does nothing.
• The audio does work. With an input source connected and playing, after plugging the TV in the audio starts by itself; that is, without having to press the POWER button first.
• The red indicator above the bezel buttons flickers in response to buttons being pushed on the remote, just like it always did. The VOLUME UP/DOWN, MUTE, and SOURCE buttons all work.
• If I push the POWER button the audio stops but the TV does not "click" off. If I push the POWER button again, the audio does not resume. If I push any button (including POWER) the red indicator above the bezel buttons still flickers in response.
• Only when I unplug the TV does it "click" off.

I took the back panel off and looked everything over and didn't find any bulging capacitors or burn marks. The only thing I found that looks damaged is the casing on a bright blue component on the Y-sustain board has almost completely cracked off on one side where it is glued to the adjacent component. Could this be the source of the "pop" sound?

Thanks in advance for any help.

[ozzy214]

Re: Samsung PN51D7000 plasma TV: No display after loud "

Yep thats your problem. GEt a y sustain. Unless you can do low level solder. Then someone else will have to chime in, because Im not sure if it is a cap or a resister.

[freakaftr8]

Re: Samsung PN51D7000 plasma TV: No display after loud "

Do yiu have any blown fuses on the y sustain? Are you checking any voltages coming off the power supply?

You may have a shorted buffer board that caused this

[BACONputing]

Re: Samsung PN51D7000 plasma TV: No display after loud "

Do yiu have any blown fuses on the y sustain? Are you checking any voltages coming off the power supply?

You may have a shorted buffer board that caused this

I see several fuses on the power supply board but none on the Y sustain. Unless I'm looking for the wrong thing?

I do not have a multimeter at the moment with which to test. What/where would I be checking on the power supply?

The buffer board is the same as the scan drive, correct? Would that mean both that and the Y sustain would need to be replaced?

[BACONputing]

Re: Samsung PN51D7000 plasma TV: No display after loud "pop"

Do yiu have any blown fuses on the y sustain? Are you checking any voltages coming off the power supply?

You may have a shorted buffer board that caused this

If I check Vs on the power supply and other boards I consistently get only 0.4V. For Va I get only 0.03V. If I check the pins labeled 5.3V on the cables from the power supply to the logic and main boards I do get the correct voltage.

Also, looking closer at the components on the power supply as seen in the attached photo, are those leaking or is that glue? The bottom one in particular has yellowish gunk all down its sides.

[BACONputing]

Re: Samsung PN51D7000 plasma TV: No display after loud "pop"

I think I'm getting somewhere.

I disconnected all three connectors from the Y-sustain board. Now when I turn the TV on the LED on the logic board turns on for a half second every second. Using the test points on the power supply board, for Vs I get 208V (sticker says 207V) and for Va I get 58V (sticker says 58V).

This would seem to indicate either the Y-sustain and/or Y-buffer boards are at fault. Is it to be expected that, with a bad Y-sustain board connected, I would get readings close to 0V for Vs and Va? Does getting (close to) the correct voltages with the Y-sustain disconnected put the power/main/logic/X-sustain boards in the clear, or could there still be problems with them, too?