Lg 50pk250

[VivianLarrieu]

Hi,

I found a LG 50PK250 but on the first test, the TV does not have image, just sound.

I check some voltage, Va and Vs have some stability problems and I found that some soldering should be repaired. After that, Va and Vs are good.
The D1 blinks on the controller board, the TV is live, but still no image...

I check others voltage, all others seems good except VSC and VY. They are close of 0.
So, I suspect the Y-Sus board have one or more components to change.

I check all FET and found some to be replace (Q405, Q408, Q412, Q414 & Q415).

I check all Y-Drive connectors (upper & lower) in diode mode and I do not found any problem.

I also check the different internal voltage, FG5V, FG10V, FG11V, FG15V, FG24V and 18V are good.

I also check the Y-Drive boards for shorts and do not find any problem (check all connectors in diode mode... long process).

So, I order the five FET and change them.
Then, I connect the Y-SUS board again without connecting the Y-Drive boards.
Power-up... no VSC & VY, still around 0.
I try again with the Y-Drive boards in case the load is not sufficient to start correctly the board.

This time, one of the new FET (Q405) exploses....

I suspect another problem, but I need your help to find the problem.

Thanks
Vivian

[tvtimmy]

Re: Lg 50pk250

The new ones are probably fakes from China. Always test new ones before installing.

[VivianLarrieu]

Re: Lg 50pk250

Thanks for the advice.
Where do you recommand to purchase these 30F124 ?
I found only some on ebay.

[tvtimmy]

Re: Lg 50pk250

It's been along time and I can't remember who I bought them from. Ebay doesn't go that far back for me to check either. My advice is order from someone that posts a picture that looks like the original and takes returns. I explained that I know how to test them and then they refunded my money without having to send the fakes back to them.

[R_J]

Re: Lg 50pk250

It is also possible that when the mosfet shorted it also damaged the gate drive circuit as well.