no picture on my samsung 50 inch plasma

[jose6326]

Having problems with my tv model PN50C550G1F

When I turn on the tv the power on sound comes on but the screen is black
No functions work with the remote

I watched a few youtube videos and most of them said it would be the power supply board, y main and/or y buffer board
I visually checked all the caps and none of them were physically blown


Initially I was getting the following voltages
Vs 211 actual 80
Va 55 actual no reading
Vsc -193 actual -.084
Ve 86 actual 23
2ve 77- I cant find this test point on any board

So I bought the power supply board, y main and y buffer board on ebay
After I replaced the 3 boards I got the following voltages

Vs 211 actual 205
Va 55 actual 54
Vsc -193 actual -195
Ve 86 actual 73.7
2ve 77 - I still cant find this on any board

Now when I power on the tv the power on sound comes on and the screen illuminates for about 3 seconds and shuts off (blacks out)
I began to recheck the connections and I decided to check the ribbon cables
I disconnected and reconnected the ribbon cable from the logic board to the main board and now the screen stays illuminated.
I tried the remote and still no functions work

Another thing I noticed is that there is 2 led's on the logic board
Before I replaced the boards the led on the right would blink
After I replaced the boards the led on the right would still blink
After I reconnected the the ribbon cable from the logic board to the main board the right led turned off and now the left led is blinking not sure if this is relevant

So now I am at this point looking for help
I don't want to continue throwing boards at it
Please help and thanks in advance

[jose6326]

Re: no picture on my samsung 50 inch plasma

Here are pics of the
power supply
Y main
Y buffer
X main and buffer
Main board
Logic board

[tom66]

Re: no picture on my samsung 50 inch plasma

See here:
https://www.badcaps.net/forum/showpo...61&postcount=2

See if you get test patterns.

[jose6326]

Re: no picture on my samsung 50 inch plasma

Tom66 sorry to sound like an idiot but I do not know which is the Lvds cable

Is it the one to the main board or to the y main
I was guessing its the one to the main board but I want to be sure

I have the 4 pin connector jumpered just need to identify the lvds cable


Thanks

[tom66]

Re: no picture on my samsung 50 inch plasma

You were correct, it is the one going to the main board.

Topmost connector of this image.
https://www.badcaps.net/forum/attach...8&d=1369516918

[jose6326]

Re: no picture on my samsung 50 inch plasma

Thanks

I will get to it today when I get home from work

What test patterns am I looking for?

[tom66]

Re: no picture on my samsung 50 inch plasma

This is what it should do. (Not my video.)
http://www.youtube.com/watch?v=JCtF5...ature=youtu.be
(Ignore the flicker on the patterns: it is due to the camera.)

[jose6326]

Re: no picture on my samsung 50 inch plasma

Cool I will test it today

I will record it as well

Thanks

[jose6326]

Re: no picture on my samsung 50 inch plasma

i jumpered number 3 and 4 on the 4 pin connector disconnected the cable to the main board, turned on the tv and i did NOT receive any test pattern as shown in the youtube video you provided

the tv turned on the screen illuminated and stayed illuminated and that is it

what is the next step or do you kow the issue?


thanks

[tom66]

Re: no picture on my samsung 50 inch plasma

Yes, I have a hunch. Can I have a picture of the long thin boards that run along the bottom of the plasma panel? You may need to remove the speakers.
N.B. Do not disconnect any connections from these boards while the set still has power or you will FUBAR the plasma panel.

[jose6326]

Re: no picture on my samsung 50 inch plasma

Here are the pics of logic buffer board E and F

I also tested the fuse that is on the buffer board E and it is not blown

[tom66]

Re: no picture on my samsung 50 inch plasma

What voltage do you get either end of that fuse you checked?

[jose6326]

Re: no picture on my samsung 50 inch plasma

i checked voltage to the fuse on the logic buffer E
with power on -0.000
voltage with no power .005 then i double checked and it went to -0.000
ohms 0.1

[jose6326]

Re: no picture on my samsung 50 inch plasma

Tom66 i was reading another thread where you are helping someone with sound but no picture on a Bush (samsung) tv

the issues on that tv are similar to mine
do you think it is my xmain board? the reason i ask is because the Ve test point on the x main board reads 73.7 but should be 86

im just throwing ideas out there you are the tech

let me know

thanks

[tom66]

Re: no picture on my samsung 50 inch plasma

Not at presently suspecting X-main no.
I am thinking control or bad panel.

[Vipermarty]

Re: no picture on my samsung 50 inch plasma

Hi Jose, yes that was my thread, i've been watching yours too

[jose6326]

Re: no picture on my samsung 50 inch plasma

I really hope its not the panel

[tom66]

Re: no picture on my samsung 50 inch plasma

Dark room, confirm if you have screen glow or not.

[jose6326]

Re: no picture on my samsung 50 inch plasma

Yes there is a glow

When I turn on the tv the screen illuminates (glows) shuts off after 3 seconds then the chime comes on then the screen illuminates (glows) again and stays illuminated (glowing)

[tom66]

Re: no picture on my samsung 50 inch plasma

OK, show me how you set up the test patterns, because if that does not work you probably have a control board issue.