Samsung PN50B400P3D Sound No Picture

[fcisolutions]

Hello I have a Samsung Plasma PN50B400P3D. I have tried replacing X and Y Main and have tested the Y Buffer board for continuity. The VA and VS reading are good. I am at a loss.
Thanks in advance.

[dskall]

Re: Samsung PN50B400P3D Sound No Picture

Test pattern?

[fcisolutions]

Re: Samsung PN50B400P3D Sound No Picture

On the logic board?

[fcisolutions]

Re: Samsung PN50B400P3D Sound No Picture

[fcisolutions]

Re: Samsung PN50B400P3D Sound No Picture

Here is a picture of the components.

[dick_barton]

Re: Samsung PN50B400P3D Sound No Picture

Can you supply a focused close up picture of the board within the red box.

[fcisolutions]

Re: Samsung PN50B400P3D Sound No Picture

Picture of the logic board!

[fcisolutions]

Re: Samsung PN50B400P3D Sound No Picture

I think I might have confused yall. The VS and VA voltages are good when the y-main is disconnected (6pin to 6pin connector at the top). The y-main board we bought did the same as the original. Logic board blinks once every second when the y-main is disconnected.

[dick_barton]

Re: Samsung PN50B400P3D Sound No Picture

Picture of the logic board!

Disconnect the LVDS cable from the logic board to the main board. Place a jumper across pins 3 & 4 of the little block with pins labelled 1,2,3 & 4. Power up the set and see if the test patterns are displayed.
If they are it would suggest a mainboard fault.

[maxvalutech]

Re: Samsung PN50B400P3D Sound No Picture

You certainly are confusing when saying vs va ok when they aren't!. Also power wire to y main missing in your pic. This set about 2009 model and all indications are bad y or x side. It looks like y feeds x. The x should be disconnected and then check vs and va. Even though you have replaced the mains for both sides the buffers still suspect. One second flashing led on control board indicates good so what is it doing when y and x attached?. And my posts get tangled up too !!!

[fcisolutions]

Re: Samsung PN50B400P3D Sound No Picture

I have already tried disconnecting the buffers and x-main, and with the y main board I purchased still can not get readings. I am thinking I need another y-main.

[maxvalutech]

Re: Samsung PN50B400P3D Sound No Picture

Yes the Y side is the usual problem one in Samsung but when testing it is important to know year model as procedure different from 2010 on. The idea is to rule out boards one by one hence if x side is last in chain then test it first by disconnect etc, then proceed to y side disconnect , after that power board. The set isn't going to operate until vs and va are present with full hookup. Now just to throw in a spanner I have noted a couple of posts where even after tests indicated y or x problem it was actually power board and all I could surmise was that board Vs etc was breaking down when load applied. The logic board led flash pattern is also an indicator and should be noted down when all hooked up and not working - the flash pattern also altered from 2010. The screen output boards should be checked for shorts in the normal course and you have two of each to compare them one against the other.

[fcisolutions]

Re: Samsung PN50B400P3D Sound No Picture

Yes this is a 2009 model.

[fcisolutions]

Re: Samsung PN50B400P3D Sound No Picture

Hooked up a different power supply with the y-main isolated and still getting the same results. Thinking I have another bad y-main.

[maxvalutech]

Re: Samsung PN50B400P3D Sound No Picture

With your multimeter set to mid range ohms what readings do you get with red probe on vs input pin and black probe on gnd pin for your y and x boards all. Set off of course.

[fcisolutions]

Re: Samsung PN50B400P3D Sound No Picture

x-main vs=.024
y-main vs=1.123

[maxvalutech]

Re: Samsung PN50B400P3D Sound No Picture

And what readings do you get off the other 2 boards? That x main looks too low in comparison.

[fcisolutions]

Re: Samsung PN50B400P3D Sound No Picture

Power Supply Board
VA = 7.32 VS = 39.98

Not sure what other board you were talking about: logic or main?

[maxvalutech]

Re: Samsung PN50B400P3D Sound No Picture

Sorry you said y and x had been replaced so I assumed you now have 2 of each ?

[fcisolutions]

Re: Samsung PN50B400P3D Sound No Picture

O.K. I got you sorry about the confusion. I will check it for the other two boards. Thanks