LG 50PK950 - Turning off after 15 Minutes

[Data45000]

Hi there,

my old tv (~11,5 years) has a problem since 3 days.

After 15 Minutens watching he is turning himself off - red light is on.

When i try to turn him on - "click - clack" and going off immediately.
After ~ 20 Mins i can turn him back on.

on the Power Suppile Panal in the middle:
I opend it, and i tested the three white resitors, all three 10,2 Ohm.
The others are 0,2 Ohm.
I tried to test the capacitors, but my device can only handle 99 yF.

Is there any chance for me to save this?

Best regards from Germany

[dskall]

Re: LG 50PK950 - Turning off after 15 Minutes

Need good pictures of boards and voltages from power supply.

[Data45000]

Re: LG 50PK950 - Turning off after 15 Minutes

I only have one picture. The TV is closed again for testing.

Voltages from Power Supply????? What do you mean with this?
Did you mean the messuring while the TV is on? That is risky - i can do it not before Sunday.

[nomoresonys]

Re: LG 50PK950 - Turning off after 15 Minutes

some testing: https://www.youtube.com/watch?v=XH9GfkGQX1I

[dskall]

Re: LG 50PK950 - Turning off after 15 Minutes

Well plasmas operate with high voltages. I would suggest getting another TV. Plus, plasmas are energy hogs. Something green energy can't sustain.

[nomoresonys]

Re: LG 50PK950 - Turning off after 15 Minutes

Well plasmas operate with high voltages. I would suggest getting another TV. Plus, plasmas are energy hogs. Something green energy can't sustain.

+1000 totally agree.

[Data45000]

Re: LG 50PK950 - Turning off after 15 Minutes

Oky - atm the TV dont go on anyway - he is going back to standby immediately.

I loved the real black

OLED are so expensive ....

[Diah]

Re: LG 50PK950 - Turning off after 15 Minutes

Oky - atm the TV dont go on anyway - he is going back to standby immediately.

I loved the real black

you played with PCB as you wrote.. so it mean the PCB had crack solder joint point... inspect it all transformer points and resolder them.
BTW its good chance to shoot photos and upload here

[Unspun01]

Re: LG 50PK950 - Turning off after 15 Minutes

I agree with Diah:

If your large white ceramic resistors on the upper right corner of the power supply are not "open", then your problem is likely cracked or intermittent solder connections on the yellow jacket transformers.

Just repaired a LG 50PK250 that had your same problem - would turn on and work for a bit then turn off, or would click without turning on. The problem was identified under magnifying glass as bad solder connections to the large yellow-jacket transformers.

Re-touch with fresh leaded solder AND FLUX. You may want to also inspect all heat-sing mounted ICs like transistors or power management ICs, or bridge rectifier, etc.

Best of luck.

[Data45000]

Re: LG 50PK950 - Turning off after 15 Minutes

Hi there, thank you for the tipps, I will test it.

Here are the pictures Maybe you see something i did not see.

[Unspun01]

Re: LG 50PK950 - Turning off after 15 Minutes

The last photo of the bottom side of the power supply definitely shows bad solder connections on the large transformers T901 and T902. For sure the upper rightmost pin on each transformer needs to be resoldered. Resolder all pins to be sure. USE FLUX. And I'm talking about the large blue/yellow transformers in upper center of power supply board.

You should also inspect and resolder any ICs or mosfets or diodes mounted to the large heat sinks since they might need attention.

For now I would focus on the visibly bad joints of the transformers

[Data45000]

Re: LG 50PK950 - Turning off after 15 Minutes

Hi,

you are right, the one is broken. That makes sense, when it is getting hotter, the distance will grow.

I made the a lot of the solder points new.

Going for a test now.

Edit: 40 Minutes now, and he is running - i close the case now and test it again.

[Data45000]

Re: LG 50PK950 - Turning off after 15 Minutes

2nd Test over 1 hour and the TV is running without any problems!

I will test it the next week, but I think the Problem is solved



Thanks guys.