LG NB4530A soundbar abruptly powering off

[dlxmax]

I've had my LG NB4530A soundbar for 7 years.
It's been great up until the past few days.

After playing sound for about 30 minutes it now shuts off abruptly.
There's no "GOODBYE" message on the LCD, and the standby light doesn't illuminate.
However, I can turn it right back on, but it will only stay on for minutes (or less) before dying again.

I'm looking at the service manual (attached) and there isn't a section addressing this kind of issue.
I do have a multimeter, and a rework station, but no oscilloscope.
I've already removed the mainboard for testing. I just don't know where to start looking.

Where would you begin testing?
Thanks for your ideas!

I strive to prevent e-waste as much as possible!

[diif]

Re: LG NB4530A soundbar abruptly powering off

After 7 years, any electrolytic capacitors, also check for possible dry joints.

[dlxmax]

Re: LG NB4530A soundbar abruptly powering off

I checked some of the caps in the hottest area and they measured within spec, and I didn't spot any dry joints. I reached out to LG here in Korea about getting a replacement mainboard and they wouldn't sell me one, but they apparently still service this model so I set about putting it back together. And now it works just fine.

Since it was exhibiting the problem on my test bench before disassembly, possibly one of the ribbon cables or plugs needed reseating. Or maybe the gremlins departed when the case was opened? lol

[Th3_uN1Qu3]

Re: LG NB4530A soundbar abruptly powering off

Reminds me of the free 42" LG plasma I got from a shop. Apparently it would shut down after a few minutes. All I did was take the back off and blow the dead roaches off the sustain boards. Plugged it in and it never turned off by itself since.

[madan1]

Re: LG NB4530A soundbar abruptly powering off

Is there a heatsink on TAS5612LADDVR / ic701? If yes, change the thermal paste.