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Shahid
Shahid, Technician
Category: TV
Satisfied Customers: 10654
Experience:  I have been repairing electronic gear since 1993 as a qualified Sony tech
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I have a Samsung p50b430p2d that has sound when turned on

Customer Question

I have a Samsung p50b430p2d that has sound when turned on but no picture. I also have a Samsung hp-t4254 that will not power on at all.
Submitted: 1 year ago.
Category: TV
Expert:  Shahid replied 1 year ago.

Hello, my name is ***** ***** I'll assist you. I'm sorry you're having trouble with it. I'll assist you Samsung p50b430p2d only in this chat thread, please post another question for Samsung hp-t4254 TV because we can't troubleshoot two units in one question.
Now I need additional info to troubleshoot the issue.

- Does p50b430p2d TV screen glow/ show any light/ graphics when press power button to turn On the TV?

Thanks.

Customer: replied 1 year ago.
no it does not. I replaced the y main board. nothing. I swapped a spare buffer board but im not sure if it is good or not. unit powers on with jingle but no picture
Expert:  Shahid replied 1 year ago.

OK, can you recheck TV model number which seems missing a letter?

Customer: replied 1 year ago.
pn50b430p2d- model code is pn50b430p2dxza
Expert:  Shahid replied 1 year ago.

Thanks, ***** ***** it and get back to you in 10 minutes.

Customer: replied 1 year ago.
no problem
Expert:  Shahid replied 1 year ago.

Thanks for waiting, please check Vs and Va volts on power board at Va-TP and Vs-TP (test point) on power supply board, volts may appear for a second when press power button on TV.

What readings appear on meter for Va and Vs volts check?

Customer: replied 1 year ago.
I will have to go and get my meter. in the mean time what are we attempting to rule out?
Expert:  Shahid replied 1 year ago.

With this test we will check y-main and x-main boards to find out if any one is short and causing the problem.

Customer: replied 1 year ago.
ok. give me a few hours and I will report back. thanks
Expert:  Shahid replied 1 year ago.

OK, I want to make bit correction here, above test will confirm power supply board is working to provide Va and Vs boards to y-main and x-main board or not.

Thanks.

Customer: replied 1 year ago.
the va and vs match the sticker 209 and 55
Expert:  Shahid replied 1 year ago.

OK, so you get Va and Vs volts for a moment when turn On the TV, that means power board is working.

Did you get replacement y-main board from reputable source and was the board new?

Also, what is the part number written on old and new y-main boards?

Customer: replied 1 year ago.
I got it from sears parts direct. old # ***** ***** (aa2) NEW is lj92-01689a/b (aa3)
Customer: replied 1 year ago.
they said is was new
Expert:  Shahid replied 1 year ago.

Thanks for the info, it seems x-main board isn't working, since y-main board has been replaced and power board is working so x-main board (LJ92-01688A) seems suspected at this point and can cause no light/ picture on screen. Please replace x-main board in TV which will help to resolve the problem. I trust my input will help you out. Please feel free to respond if you have any additional questions.
A positive rating to answer would be greatly appreciated, please click on 5 star on this page then click submit/finish button so I can get credit on website for my work.
Regards,
Shahid.

Customer: replied 1 year ago.
im not wanting to throw parts at this thing. that amy be costly. How do I test to make 100 % sure it is the x main?
Expert:  Shahid replied 1 year ago.

OK, check ohms across pin-1 (Vs) and pin-4 (GND) of connector that plugged to y-main board through long harness, if you get low ohms reading such as 2~4 ohms that indicates a short on x-main board so need to be replaced.

If you get high ohms/ no reading that indicates open circuit on x-main and board will be replaced as well.

Thanks.

Customer: replied 1 year ago.
on the connector of the x main( coming from y main) I check the bottom terminal ( only black wire on connector) and pin 4 I get open. but on pin 3 it reads the same resistance as when I check with pin 1 and ground.
Expert:  Shahid replied 1 year ago.

Please check resistance only between pin-1 and 4, what readings appear on meter and what ohms scale is selected on meter to take the readings?

Customer: replied 1 year ago.
ohm 20 on dvm. xmain connector I and 4 with cable disconnected is open. pin 1 and 3 show 25 ohm resistance. pin 1 and direct ground show 25 ohm
Expert:  Shahid replied 1 year ago.

Thanks for the info, reading are bit confused and should be around 40 ohms between pin-1 and ground. It seems one or more FETs have got leakage internally and can be cause of issue so swapping this board seems only option at this point.

Thanks.

Customer: replied 1 year ago.
ok. If you are quite confident it is the x main I will replace it and get back to you. Do you have a suggested part number and source(sear, shop jimmy}?
Expert:  Shahid replied 1 year ago.

I'm confident about x-main board as there is no other obvious reason for dark screen unless the display panel itself is defected/ internally short, please check the part number written on x-main board that would be like LJ92-01688A or some thing similar to search/ google it and if ebay seller gives warranty of board then it would be fine to get it on low cost.

Thanks.

Customer: replied 1 year ago.
I ordered the X main. I will let you know when I install it upon arrival
Expert:  Shahid replied 1 year ago.

OK, take your time.

Thanks.

Customer: replied 1 year ago.
x main did not help. in fact after reinstalling the old part now tv turns on and off after 2 seconds!!!!
Expert:  Shahid replied 1 year ago.

This is odd, did you get identical x-main board having same part number?

Customer: replied 1 year ago.
yep. did the power board go out? possibly what was wrong the whole time?
Expert:  Shahid replied 1 year ago.

It was confirmed that Va and Vs volts are available that means power board is working.

What happens if you install new x-main board? What symptoms you get on TV?

Customer: replied 1 year ago.
After installing the new X main the TV will power on then off no matter what I do now.
Expert:  Shahid replied 1 year ago.

I'm running out of ideas what is causing the problem and it seems it is not possible to resolve it over internet chat and real hands of TV tech on TV are needed to sort it out. Please let me know if you would like another expert assistance so I'll repost this question to other experts to have a look.

Thanks.

Customer: replied 1 year ago.
please get someone else.
Expert:  Shahid replied 1 year ago.

OK, I'm opting out and this will repost the question.

Thanks.

Customer: replied 1 year ago.
anyone???