Buffer board 150Kohm is it good?

[claustro]

Hi guys I have a samsung plasma PN51D550 that make a pop and dead.
Now it click during power up but no sound and no image. Status led blink red.

I checked and the click stop only when I disconnect the Y-board.
I am checking the buffer board and it seems fine on visual inspection , the resistance between svc-poutl and svc- outh is 150 k ohm , should this board ok?

thx Andrea

[tom66]

Re: Buffer board 150Kohm is it good?

That seems OK.
What you should also try is with your meter on continuity mode, test from SVC-POUTL to all of the output pins that go to the panel.
On continuity mode, if your meter beeps quickly (most do), you can run it down all of the pins quickly. If it beeps, go back and check, because that could be a fault.
You need to make sure the panel is not cracked with this model, as cracks can cause the symptom you see.

[claustro]

Re: Buffer board 150Kohm is it good?

I checked the buffer board as you suggested and I don't have shorts there.
Shuold be enough replace y-sustain board based on my description ?

If I disconnect x-main the power supply keep clicking
If I disconnect the Y-main the power supply stop clicking ( the green led on main board switch on for about 5 seconds and then off for 1 second)

Is it possible that the screen cracks by itself without physical trauma? I should see a crack simply visually inspecting the surface?

Also I checked tha Ymain buffer connector and it seems to me that something is wrong there. Only the first one isn't' in short , the second and third is totally in short and the last one only the last 4 pins aren't in short with what I suppose is the ground pin.
OI also checked some diodes and resistor ,the only problem I fund was some 103 smd resisotr misured of 5.6kohm instead of 10k ohm ( i have very very basic knowledge of elettronics)
Is this a prove aof a faulty Y board?

thank you very much for your help.
Andrea

[claustro]

Re: Buffer board 150Kohm is it good?

I also checked transistor
the model is 30G124 http://www.datasheetcafe.com/30g124-datasheet-pdf/and I checked between collector and emitter ( is it right?) and 4 of 6 transistor in the board are in short

[tom66]

Re: Buffer board 150Kohm is it good?

If you cannot see a crack, it is probably ok.
I would check both X- and Y- boards for short circuits.
It may be necessary to replace both if there are shorts on both.

[claustro]

Re: Buffer board 150Kohm is it good?

Thank you for your replay , I'll check the X also as soon as possible. Do you think I could damage the new Y board If I'll miss an X board short ?
I found the y- board on ebay quite cheap .
It would be great not to buy a new TV :-)

[tom66]

Re: Buffer board 150Kohm is it good?

Thank you for your replay , I'll check the X also as soon as possible. Do you think I could damage the new Y board If I'll miss an X board short ?
I found the y- board on ebay quite cheap .
It would be great not to buy a new TV :-)

yes it could possibly damage the Y so check the X thoroughly.

[claustro]

Re: Buffer board 150Kohm is it good?

My tv is repaired !!
Thank you very very much for you kind help .

Andrea

[tom66]

Re: Buffer board 150Kohm is it good?

Glad to hear and thanks for the update

[claustro]

Re: Buffer board 150Kohm is it good?

Hi all ,
My tv exploded again , the last board lasted only 2 months.
I sent a message were I bought the board and he asked me if I checked the voltages before installing the new board.
I didn't becouse I didn't know which voltage check.
Now I can replace the board again for 20 euros but I would like to trash this also.
Can someone help me telling me what I should check before install the replacement part?

thx
Andrea

[tom66]

Re: Buffer board 150Kohm is it good?

You can check -Vy and Vsc voltages. -Vy is around -200V and Vsc is around 150V.

But, if the voltages were bad, it's very likely your picture would be bad anyway.
So the failure is probably random. Sometimes it happens. The boards are used, so they won't always last as long as a new board.

[claustro]

Re: Buffer board 150Kohm is it good?

thank you for your replay.
The picture was perfect but the tv was active only for about 40 hours from last failure.
Do you think could be worth make another try or you'll give up and buy a new tv?

I have 2 option in mind
HISENSE H55N6800 515 euros
or make the jump with
LG OLED55B7V at 1400 euros

[tom66]

Re: Buffer board 150Kohm is it good?

The OLED is better if you want to get a TV comparable to the plasma's picture quality.

Personally, I was quite fond of the D550 when I fixed mine, and it can be quite reliable. For 20 euros, I feel like it's worth trying again. If it fails again, then there must be something wrong so maybe get a new TV then.

[claustro]

Re: Buffer board 150Kohm is it good?

thank you Tom your advise seems reasonable.
I don't cae to much of ultraHD content and I like plasma images.
I'll kepp ypu posted

thank you