Help identify boards in Samsung plasma

[jaxmc1023]

Our 54-week old 51" Samsung plasma TV (PN51E530A3FXZA) suddenly stopped showing a picture last night. It is mounted on the wall, and the picture/sound is provided by HDMI from all sources. Would sound still be available if source is HDMI?

Checked the Va and Vs on the power supply board. If checked when TV first turns on, the voltage starts out at the normal range and then steadily drops out to near 0.

To my inexperienced eye, I am only seeing one fuse on this whole TV -- on the power supply board. Ohm check there matches the reading when testing the two probes of the DMM together.

The green LED on the Logic board is flashing very slowly -- maybe 5 seconds on and two seconds off..?

I was going to try and isolate the Y-Sustain, Z-Sustain, etc., but my unit does not have the same boards as most guides I'm seeing on the web.

Are my Y-Main and X-Main on the same board?

Thank you for any help you may be able to provide!

[Hamie]

Re: Help identify boards in Samsung plasma

Y-sus and buffer to the left.
Doesn't have an the more Conventional XMain - just has an xbuffer.

Your power supply probably isn't the issue as most samsung nowadays show the voltage then shut down once the error is detected.

More than likely your y-sustain is bad.
also Check the buffer ICs for shorts.

[jaxmc1023]

Re: Help identify boards in Samsung plasma

What's the process for checking the Buffer ICs? Sorry, i'm learning this on the fly...

and thanks for the response!

[Hamie]

Re: Help identify boards in Samsung plasma

here you go.

https://www.youtube.com/watch?v=5hVi5gd0aec

[jaxmc1023]

Re: Help identify boards in Samsung plasma

Replaced the Y-Buffer and Y-Sustain.. When trying to turn the TV on, it flashes static briefly (less than a second) then goes black. No menu.. Green light blinking once every 5 seconds

Any ideas what I should try and track down next?

[Shinju]

Re: Help identify boards in Samsung plasma

Either you got bad replacement parts or your power supply voltages are off.

[crt man]

Re: Help identify boards in Samsung plasma

Hi
Did you check the Y buffer for shorts?
If yes, then do the same with your replacement,
I feel it may also be faulty.

Alan.

[tom66]

Re: Help identify boards in Samsung plasma

Check the panel extremely carefully for a micro-crack on the edge of the panel. Does it look like this when it flashes? (with a possibly corresponding area which is dark where the panel is chipped)

[jaxmc1023]

Re: Help identify boards in Samsung plasma

Check the panel extremely carefully for a micro-crack on the edge of the panel. Does it look like this when it flashes? (with a possibly corresponding area which is dark where the panel is chipped)

no the "flash" it not nearly that dense.. also, it is very quick, and from what i can tell, does not produce the same pattern every time.

my Y-Buffer is laid out a little differently than the one shown in the "short check" video posted earlier in this thread...

when testing across the test points SVC_OUTL and SVC_OUTH i get resistance to infinity. also checking across pins 1 or 2, and any of the other pins on the connectors between the Y-Sus and Y-Buffer, I get infinity.

I don't know if it matters, but the Samsung logo also does not light up on the front of the TV.

[jaxmc1023]

Re: Help identify boards in Samsung plasma

When I turn the TV on, the VS test point on the power supply board starts out at 200+V, and then drops out to 0. VA test point starts out around 60V and drops out to 0.

Voltages at the CN801 (connects power supply to main board) connections are all normal..

It's acting as if there is a short, but I can't figure out where it is

If I disconnect the power supply from the X-Main/Y-Main/Y-Buffer (there is only one power cable to them), the voltage stills drops out at VA & VS, but at a noticeably slower pace

[jaxmc1023]

Re: Help identify boards in Samsung plasma

One last note and then I will wait for responses:

Checking voltage on VS_On. When TV is powered on, the voltage at VS_On goes from 0v to 3.3v, but then immediately drops to 0v. The drop to 0 coincides with the screen briefly flashing on and then turning back off.

[jaxmc1023]

Re: Help identify boards in Samsung plasma

Since the X-main and Y-Main and Y-Buffer all share one power supply connection (through the x-buffer board).. would that mean that they are not the cause of the voltage drop?

[tom66]

Re: Help identify boards in Samsung plasma

The voltage drop is caused by the control board, it is shutting down the power because it detects a fault with the X-main (or X-buffer), Y-main or Y-buffer.

[jaxmc1023]

Re: Help identify boards in Samsung plasma

Since the voltage drop still occurs with the Y-Main/X-Main/Y-Buffer all disconnected from the power supply, would that point to the X-Buffer being the fault? Or would the fault be the mere fact that none of those boards have power?

Thanks again for your help

[tom66]

Re: Help identify boards in Samsung plasma

If the control board detects the boards not being present, this will cause a similar fault - it's a pain in the behind...

The best you can try is checking Vsc, Ve and Vsch (where available) while it powers up; see if the voltages are steady or if they disappear.

[jaxmc1023]

Re: Help identify boards in Samsung plasma

How does the logic board get power? My version does not have the typical power connectors -- only ribbon cables.

I also noticed this morning that the replacement Y-Sustain/X-Main board that I received is Revision AA3, while the board being replaced was Revision AA7. The replacement board has a capicitor and potentiometer at VE, while the original board did not have these components. I made certain to check the part# stickers on the items before buying them, but the seller apparently just ships whatever he wants.

[tom66]

Re: Help identify boards in Samsung plasma

I think the logic board gets power from the X-buffer/X-main board; the power and control signals go to the C-buffers, and these are then routed into the control board assy.

[jaxmc1023]

Re: Help identify boards in Samsung plasma

So the X-Main is NOT combined with the Y-Sustain/Main board? It is actually part of the long skinny board on the right side of the panel?

[Alastair E]

Re: Help identify boards in Samsung plasma

Nah--In your set, the X-Main is the thin board on the right! In some sets, its even part of the PSU!

These newer sets (and some older ones....) monitor the output signals from both 'SUS' boards, and if they are not right--as in wildly out in size, shape etc, or absent-- the control-board will shut down the power-supply rails, Vs and Va....

[jaxmc1023]

Re: Help identify boards in Samsung plasma

Wow, well that's interesting news..

So, looking at the picture in the original post, there is no way to isolate the X-Main from the Y-Main/Y-Buffer is there? The boards on the left side cannot receive power without power first being provided to the X-Main, correct?