LG 50PJ350 - No power (not clicking), let sit, then it's fine

[monkeylizard]

I have an LG 50PJ350 that had the clicking problem. The resistor in the upper right was clearly blown and had a burn mark on the PCB. My brother (an electronics tech) installed the repair kit for the EAY60968701 power supply board from Coppell TV Repair. That fixed the problem.

About a week or so later, the set would not power on at all. No standby light, no clicking, no sound, nothing. I unplugged it for a few hours and plugged it back in. Still nothing.

I unplugged it again and set it to the side for a day or two, then plugged it back in and it worked great. That lasted about a week or so and now the problem is back.

No signs of power at all. I can unplug, plug in and still nothing, but I let it sit overnight unplugged and it works again.

It's currently working, but I suspect the problem will appear again any day now.

I don't know if unplugging it is necessary or if simply letting it sit idle for a few days plugged in would have a similar effect. I haven't tried that yet.

I don't see any obviously domed caps or any other burn marks besides around the hole for the original blown resistor.

Any ideas?

[monkeylizard]

Re: LG 50PJ350 - No power (not clicking), let sit, then it's fine

Update:
As expected, after a day or two, it stopped working again. No power standby light, no clicking, nothing.

Then the clicking returned for a while, then it stopped.

Now the TV powers on.

The solder points on all of the new parts look solid. Is there a good way to test each part that was replaced in the repair kit? Maybe I got a bad resistor, or one with tolerances too loose for the board? Or maybe I do have a bad solder point?

[ReeceyBurger123]

Re: LG 50PJ350 - No power (not clicking), let sit, then it's fine

Sounds to me like failed motherboard, maybe run the test patterns see if it clicks when doing that ?

[mohomane]

Re: LG 50PJ350 - No power (not clicking), let sit, then it's fine

hi i had the same set as above,but i replaced the y-sus board the set switched okay with a dark picture,but Vs 201 ,Va 55 as indicated on the board but -Vy was 209v instead of 200v when i tried to adjust it switched off .the y-sus is new board.

[sordids999]

Re: LG 50PJ350 - No power (not clicking), let sit, then it's fine

I had the same fault the other day ended up being cold solder joints on the power supply
Maybe worth a try checking this

[smuddge]

Re: LG 50PJ350 - No power (not clicking), let sit, then it's fine

what are the parts in this repair kit.
i have same problem and I am pretty sure after testing everything this is what it needs.
i would buy the repair kit from coppel but the shipping to canada is 45$ US alone.
clearly not worth that money when the repair kit is 15$.

will just order what i need from digikey.

anyone with any knowledge of this any help here would be appreciated.
thanks

[smuddge]

Re: LG 50PJ350 - No power (not clicking), let sit, then it's fine

just ordered from their website. no shipping cost there.
ebay has a huge shipping cost.
all good thanks anyways.

[CapLeaker]

Re: LG 50PJ350 - No power (not clicking), let sit, then it's fine

yeah... unfortunately we Canucks are getting hosed with E-Bay shipping from the US.

[monkeylizard]

Re: LG 50PJ350 - No power (not clicking), let sit, then it's fine

Update: With no changes by me, the set has worked fine for about 3 weeks or so. Then this past weekend the problem returned. After I turn the set off, the idle power red light is on. I can turn the set back on and off. Seems to work fine. then after some seemingly random amount of time I'll walk by the powered off set and see that the standby light is off. No clicking, nothing. It will not power on at this point. Some seemingly random time later, the standby light will be on and the set will power on just fine.

As long as the standby light is on, the set works fine. After powering off, the standby light will be on, but will eventually go out and there's zero response. Then the standby light returns and it works fine.

I'm leaning towards a cold solder joint, but my brother's time (aka my solder tech) is hard to get, so I think I'll get another repair kit and have him put that in. That should fix any cold solder points and eliminate any questionable parts in the kit.

[CapLeaker]

Re: LG 50PJ350 - No power (not clicking), let sit, then it's fine

Check if you lost STBY voltage when that LED is out.