Sanyo plasma- samsung s42ax-yb08 panel-psu squeal no picture

[tw2005]

I need help with an Australian SANYO PLASMA- SAMSUNG S42AX-YB08 PANEL-PSU SQUEAL NO PICTURE.

This one has me stumped and I'm beginning to think I have a bad panel but not having the experience hopefully someone else can give me a clue.

Symptoms are:

power connected set in stdby, turn on, front led goes red, ctrl logic card led starts blinking then at the point the panel is initialised, no picture, not even a flash in the panel, horendous buzz and squeal from the PSU oscillating every few secs high ptch, then lower pitch. all voltages appear normal.

Y-buffer replaced, same result, metered out all inputs of the y,x-main boards, no obvious shorts.

Totally confused.

Panel and drive boards are the same as in these models as well.

EMERSON PL-P42W-10A
INSIGNIA NS-P42Q-10A
SAMSUNG PN42A410C1DXZA
SAMSUNG PN42B400P3DXZA
SAMSUNG PN42B430P2DXZA
SAMSUNG PN42B450B1DXZA

[tom66]

Re: Sanyo plasma- samsung s42ax-yb08 panel-psu squeal no picture

Sounds a lot like a bad panel sadly, it's a common symptom with certain thin Samsung plasmas (as well as other plasmas) to have a loud buzzing sound with a bad panel; it's due to some internal short in the panel I believe.

[tw2005]

Re: Sanyo plasma- samsung s42ax-yb08 panel-psu squeal no picture

Hmmm, thanks. Yes it is sad, win some lose some. time to scrap the boards I guess.

Anyway to confirm bad panel?

thanks mate.

[tom66]

Re: Sanyo plasma- samsung s42ax-yb08 panel-psu squeal no picture

Hmmm, thanks. Yes it is sad, win some lose some. time to scrap the boards I guess.

Anyway to confirm bad panel?

thanks mate.

If you're getting good supply voltages into the sustains and they are buzzing, you should see some light if the panel is good. Also, try inspecting the panel carefully; you can usually find the crack.

[tw2005]

Re: Sanyo plasma- samsung s42ax-yb08 panel-psu squeal no picture

If you're getting good supply voltages into the sustains and they are buzzing, you should see some light if the panel is good. Also, try inspecting the panel carefully; you can usually find the crack.

I have not seen any cracks but the PSU is makin too much of a racket to hear the sustains. It's one of those noises that appears to come from everywhere but seems to be from the PSU.

I've tried it in a dark room and don't see a glimmer of life apart from the standby light changing and the activity LED blinking on the CTRL Logic board.
Then squealing buzzing noises when it turns on the panel(if it was working).

I hate giving up on it but I'll think I'll make this one a time filler when I have nothing else to play with.

I may post up some shots of the PSU just in case it's in a different model some one has worked on. It does have a red LED onboard which I think suggests a power fault but I can't remember now what I was doing to make it activate.

No schematics or info on the PSU being a chinese special.

[heavymachines]

Re: Sanyo plasma- samsung s42ax-yb08 panel-psu squeal no picture

hi i been working on this very same set similar symptoms but no squeal, this thing has me stumped , here is what i did i disconnected y main and power board will have all proper voltages soon as i connect ymain set will power on then power off, once in a while i could get a static picture on the set, but it made a loud humm noise and never got a picture again.

so i replaced the ymain despite it never showed a short and the buffer shows no short....and as you guessed it same results and no static, so i short ps-on to ground to try to get a test pattern ,nothing but it does try because it makes that famous samsung chime every time even on normal power ups...

and again disconnect ymain power board will stay on and all voltages are good...
panel number is s42ax-yb08 i think i may have a dud panel not sure thou

y-main was purchased from shopjimmy and never ever had them send me bad parts before so i highly doubt that is the problem... now if i jump 3.3 with a 180ohm resistor volts to vs-on i can get the y main to stay powered up but still nothing on screen not even a hint of life....

[heavymachines]

Re: Sanyo plasma- samsung s42ax-yb08 panel-psu squeal no picture

could buffer be bad and not show shorts? don't think main board is bad due to chimes and power button response ....


i am ready for any suggestions ....

going to upload pics shortly...

[heavymachines]

Re: Sanyo plasma- samsung s42ax-yb08 panel-psu squeal no picture

here is layouts etc....

[heavymachines]

Re: Sanyo plasma- samsung s42ax-yb08 panel-psu squeal no picture

any ideas /suggestions or conformations would be great, i have learned alot in my journey of repairing tv's , however find myself still learning..

[heavymachines]

Re: Sanyo plasma- samsung s42ax-yb08 panel-psu squeal no picture

tom? budm anybody?

[tom66]

Re: Sanyo plasma- samsung s42ax-yb08 panel-psu squeal no picture

Check -Vsc, Ve?
budm does not fix plasmas.