LG 32LN530B-UA Randomly shuts off

[shadetreetrader11]

I have a LG 32LN530B-ua that after about 10 min or so it will just randomly shut off. Took the psb out and looked for any solder connections that have gone bad. Nothing, No bulged caps. I messured them with ESR meter and everything seems ok. Took a heat gun and warmed up different components and also used freeze spray with no affect. I also went into the settings and changed the powersave mode from automatic to off. So at this point I'm lost. All the voltages going from the psb to the main board are good. Anyone have any ideas?

[dskall]

Re: LG 32LN530B-UA Randomly shuts off

Does it shut down or just lose picture? You can monitor ps_on. Have you tried heating main board. What is the dc voltage on main capacitor when on?

[shadetreetrader11]

Re: LG 32LN530B-UA Randomly shuts off

I have tried heating up parts on the main board as well. Have tried lightly tapping on components on both main board and PSB board with a small plastic tool. Have tried to clean all the connections from board to board. Can't make it fail. The voltage on the main caps with power off is 169.5. And with power on it varies from 161-164.4.

[shadetreetrader11]

Re: LG 32LN530B-UA Randomly shuts off

And it does shut off. I have to hit the power button again to turn it back on.

[dskall]

Re: LG 32LN530B-UA Randomly shuts off

What is voltage printed on main cap?

[shadetreetrader11]

Re: LG 32LN530B-UA Randomly shuts off

450 volt
I also unplugged the wire going to the control board? ( Pwr, vol, channel, menu) . I'm took the batteries out of the remote also. I'm probably reaching a little.

[shadetreetrader11]

Re: LG 32LN530B-UA Randomly shuts off

[dskall]

Re: LG 32LN530B-UA Randomly shuts off

With tv on you should be getting around 390dcv on main cap. Seems to be something wrong with pfc on power supply.

[R_J]

Re: LG 32LN530B-UA Randomly shuts off

once the tv is turned on, unplug the cable that goes between the buttons and the main board, I suspect the power button tac switch could be the cause.

[shadetreetrader11]

Re: LG 32LN530B-UA Randomly shuts off

450 volt
I also unplugged the wire going to the control board? ( Pwr, vol, channel, menu) . I'm took the batteries out of the remote also. I'm probably reaching a little.

I said control board. I should have probably said buttons instead.

[R_J]

Re: LG 32LN530B-UA Randomly shuts off

I missed that. I see you also tried tapping the boards, have you removed the power board and looked at the solder connections on the larger components like the transformers, coils and the ones attached to the heatsinks?

[shadetreetrader11]

Re: LG 32LN530B-UA Randomly shuts off

I did inspect all the solder connections and they really look good.
One thing I was wondering about is the back lights. Is there a way to see if one of the backlights are randomly faulting.
And also the 390vdc that dskall was talking about.

[R_J]

Re: LG 32LN530B-UA Randomly shuts off

The power supply does not have a pfc circut, so 170 volts dc is fine. Its a universal input 100-240 volt ac input.
If the backlights went out, then usually, but not always, you would still have sound
Try unpluging the backlights from the power supply and see if the tv comes on. If it comes on and you have sound (no pic without BL) then I doubt thats the problem
Shopjimmy does offer an eeprom for this model, maybe thats the problem, but if the eeprom is bad the tv usually won't turn on

[shadetreetrader11]

Re: LG 32LN530B-UA Randomly shuts off

I unplugged the back light and the video and audio where still there. So your right about that.

[R_J]

Re: LG 32LN530B-UA Randomly shuts off

I would suspect something on the main board is the cause, (bad bga ic) also if you have something using the hdmi plug, remove that as a possible source of the shutting down.

[shadetreetrader11]

Re: LG 32LN530B-UA Randomly shuts off

Is that bga ic a form of an eprom? I took the power supply board off and took kind of a shotgun approach and retouched up ALL the solder joints and it didn't change anything. It still turns randomly shuts off.

[R_J]

Re: LG 32LN530B-UA Randomly shuts off

No the eeprom is IC1300, the bga type would be IC1201 and IC101

[shadetreetrader11]

Re: LG 32LN530B-UA Randomly shuts off

Little 32" TV isn't worth what they want for a used main board. Wish I knew what ic it was that is faulty. Would probably be pretty hard to figure it out because it's so random. Maybe I'll find the same TV with a cracked screen and I can use it for parts. Thanks for your help guys.

[shadetreetrader11]

Re: LG 32LN530B-UA Randomly shuts off

Replaced the main board now the image is upside down. GRRR!!!!

[shadetreetrader11]

Re: LG 32LN530B-UA Randomly shuts off

Mirrored the screen and now it seems to work good. Ended up buying a service remote to get it done. Thanks for all the help