LG 50pg20 plasma - sound but no picture. TV tries to start

[bmschiizz]

I have a 50 inch plasma that I suspect the Y-sus has gone bad

When powering up the set up the screen will light up for less than a second. then go black. you can also hear the y-sus start to hum. then stop at the same time. I also observed the VSC and VY voltage rise a bit, then drop down to close to 0V.

The TCON boards buzzes vary by jumping the test pins on the TCON board. This board should be fine.

unplugging the YSUS <-> TCON connection causes the set to do nothing upon power up. All other disconnections do not change the original symptoms.

Am I on the right page? YSUS for these are pricey. I want to be sure before I pull the trigger. Component repair would be ideal.

http://imgur.com/a/TYzxf

I will attach pictures in thread when I am able

[bmschiizz]

Re: LG 50pg20 plasma - sound but no picture. TV tries to start

Forgot to mention that all voltages to the Y-sus and main board are normal.

[ReeceyBurger123]

Re: LG 50pg20 plasma - sound but no picture. TV tries to start

Unplug the upper buffer and try to power on.

[bmschiizz]

Re: LG 50pg20 plasma - sound but no picture. TV tries to start

No change in result. Except that just the bottom half of the screen tries to start up.

I should mention that I removed both buffers and checked them for shorts.

[ReeceyBurger123]

Re: LG 50pg20 plasma - sound but no picture. TV tries to start

Ok checked the Ysus for S/C ?

[bmschiizz]

Re: LG 50pg20 plasma - sound but no picture. TV tries to start

What would the procedure for this be?

[ReeceyBurger123]

Re: LG 50pg20 plasma - sound but no picture. TV tries to start

Same as checking the buffer, in diode mode if a short is found it will beep or show 0 ohms. Check all the Igbts

[bmschiizz]

Re: LG 50pg20 plasma - sound but no picture. TV tries to start

I recall testing all the IGBTs (the 4 pin components that look like transistors) and was not able to find a short. I ended up buying a Ysus board and it solved the problem.

[moakley1970]

Re: LG 50pg20 plasma - sound but no picture. TV tries to start

I have a LG 50PG20 plasma TV and I am having this same issue. I have 2 of these TVs but only one is having this issue. the other has horizontal lines in the screen that I can't live with so I'm trying to fix the one that has a great picture. I took the power supply out of the TV that has the lines and put it in the other good TV and now I am having this 3 blinking blue lights then red light, but the TV that has the lines works perfectly with the same power supply with no issues. I don't get it. What board could be bad to cause this issue outside of the power supply?