LG 60PV250 - Erratic shut off

[hoodles]

I'm having an issue where my LG 60PV250 will randomly shut off into standby mode.

This problem started out infrequently and became worse and worse over a few days. At this point I can barely get a picture for a a second or two before I hear the relay click, the screen shut off, and the red LED standby light come on.

As a layman, I assume its the power board. I don't see any bulged capacitors, but that's about as far my troubleshooting skills go in terms of televisions.. Hopefully I can solve this during power off since these large voltages/amperages scare me a bit.

Thanks guys

[Hamie]

Re: LG 60PV250 - Erratic shut off

Unplug the z-sus try to turn on the tv, it turns on and stays on you have a faulty z-sus.

If so, remove the z-sus and inspect the solder of the coils located here:

[hoodles]

Re: LG 60PV250 - Erratic shut off

Unit seems to remain powered when unplugging z-sus. It did turn off once, but I believe it was on an unused input and triggered the "no signal auto off."

Attached is a picture of the solder joints on those coils. They look fine to me, should I try reflowing?

[Hamie]

Re: LG 60PV250 - Erratic shut off

Yes

this one doesn't look fine.

Is the fuse still good on the z-sus?

[rockit711]

Re: LG 60PV250 - Erratic shut off

If the above doesn't bear any fruit then there's a pretty simple test that can help further diagnostics.


Most LG TVs have a Auto-on function, where the PSU and sustain boards turn themselves on without the mainboard connected (triggered by the "auto GND" pin on the PSU-mainboard power connector).

To try it unplug the mainboard (both power and the flat cable next to the power plug). It should power up and the screen should *very* dimly illuminate (it can be very hard to notice especially in a bright room (far easier in a darkened room), I found it helps to have someone watching the screen while you plug it in, that way they can focus exclusively on the screen and watch for the slight shift as it turns on) There will be nothing on the screen of course but if it stays on in this mode it would be unlikely to be caused by either of the sustain boards.

Depending on what happens this can help point you at components worth looking into further.

With the mainboard disconnected there would naturally be no standby light, so you would have to judge if it is still on by the screen still being lit (or relay clicks etc).


Also if your logic board (the small board pretty much dead center with the 6 flat cables going into it) has a "EXT_AUTO_GEN" (or something similar marked on it) you can put the TV into a diagnositcs mode where it will display test patterns without the mainboard plugged in - this can be extremely useful for isolating if the mainboard is faulty. This generally involves putting a jumper over pins, or between holes on the board. I cant see it marked on your board unfortunately but perhaps it could be marked on the back. It looks like it should be the two holes to the right and slightly below the main chip, but without markings its hard to know if it is the auto generator or something else.

[hoodles]

Re: LG 60PV250 - Erratic shut off

Yes

this one doesn't look fine.

Is the fuse still good on the z-sus?

I reflowed the solder on each of the 6 coil pins, and the fuse was still good. I plugged it back in and tried turning it on... there's a buzzing and the screen stops priming. Audio, no video. Could I have botched the solder job? Also, I saw that two pins are soldered together on the P103 connector to the Z sub buffer board on the right (pic attached). Normal?

[hoodles]

Re: LG 60PV250 - Erratic shut off

If the above doesn't bear any fruit then there's a pretty simple test that can help further diagnostics.

....

Thanks for the tips. I will definitely try this out after I determine whether I messed up these reflows on the zsus.. The tv is no longer randomly shutting off into standby with the zsus disconnected, so I can assume it's that board that's faulty, correct?

I would just board swap, but there's literally 0 if these on the internet.

Also, there is a pic of the logic board in the op. Unfortunately I don't see any markings similar to EXT_AUTO_GEN.

[Hamie]

Re: LG 60PV250 - Erratic shut off

Still need to know if the fuse is open?

[hoodles]

Re: LG 60PV250 - Erratic shut off

Still need to know if the fuse is open?

Tested for continuity, fuse is still good.

[dick_barton]

Re: LG 60PV250 - Erratic shut off

Also, there is a pic of the logic board in the op. Unfortunately I don't see any markings similar to EXT_AUTO_GEN.

I think you bridge the two holes next to R51 & R52 using a piece of wire or paper clip.

[hoodles]

Re: LG 60PV250 - Erratic shut off

If the above doesn't bear any fruit then there's a pretty simple test that can help further diagnostics.


Most LG TVs have a Auto-on function, where the PSU and sustain boards turn themselves on without the mainboard connected (triggered by the "auto GND" pin on the PSU-mainboard power connector).

To try it unplug the mainboard (both power and the flat cable next to the power plug). It should power up and the screen should *very* dimly illuminate (it can be very hard to notice especially in a bright room (far easier in a darkened room), I found it helps to have someone watching the screen while you plug it in, that way they can focus exclusively on the screen and watch for the slight shift as it turns on) There will be nothing on the screen of course but if it stays on in this mode it would be unlikely to be caused by either of the sustain boards.

Depending on what happens this can help point you at components worth looking into further.

With the mainboard disconnected there would naturally be no standby light, so you would have to judge if it is still on by the screen still being lit (or relay clicks etc).

I disconnected all the connections on the main board and plugged the unit back in. There's the normal first click, and then a second relay click of the unit powering off. Screen does not prime and stay lit, even dimly.

Note: I'm pretty sure I was getting the second click after I did the solder..

[hoodles]

Re: LG 60PV250 - Erratic shut off

Bump, I'm stuck :/

[hoodles]

Re: LG 60PV250 - Erratic shut off

Found a working z-sus and swapped the board out this evening. For a glorious few minutes, I thought my problem was solved.. Unfortunately, I am back to square one with the unit working perfectly except turning off every <1min or so.

Any advice on something else I could try swapping? I'm sure I could find a y-sus; and I doubt it's the mainboard.

[cliff_hootarski]

Re: LG 60PV250 - Erratic shut off

Post #10 from Dick Barton, I would agree with him for the test pattern.
Bridge those two points and unplug the LVDS cable(blue connector) then plug the TV in.
If you get test patterns and the TV stays on, you've got main board problems.

[hoodles]

Re: LG 60PV250 - Erratic shut off

Unit randomly turned off during test patterns with the mainboard unplugged. Also got a random turn off with the new zsus unplugged.

What does that leave? Logic board, power, and ysus?

[hoodles]

Re: LG 60PV250 - Erratic shut off

Post #10 from Dick Barton, I would agree with him for the test pattern.
Bridge those two points and unplug the LVDS cable(blue connector) then plug the TV in.
If you get test patterns and the TV stays on, you've got main board problems.

Sometimes I can get a test pattern for up to 20 minutes, sometimes it's only for a few seconds. It's very random, but always shuts off eventually..

Power boards on eBay aren't too expensive; would this be my best bet?

Thanks guys

[vinceroger69]

Re: LG 60PV250 - Erratic shut off

Can you use a hair dryer and heat the boards one at a time and see if you can make the fault happen quicker? or get a fan and aim cold air at one board a time and try too get the set too stay on longer, failing that yes i would try a replacement power supply if a resonable price you can always resell it i guess if it does not solve the issue.

[hoodles]

Re: LG 60PV250 - Erratic shut off

Power supply replacement resolved the issue. Thanks for all the help and info

[seismicpulse]

Re: LG 60PV250 - Erratic shut off

Not sure if I should make a new thread but I'm having the same issue with the same tv. I went ahead and replaced the main board with a used “tested good” main board off of eBay but it's still turning off after about 15 minutes. Any thoughts?

[seismicpulse]

Re: LG 60PV250 - Erratic shut off

Not sure if I should make a new thread but I'm having the same issue with the same tv. I went ahead and replaced the main board with a used “tested good” main board off of eBay but it's still turning off after about 15 minutes. Any thoughts?

This is the back of my zsus at the coils. Apparently the previous owner did some “soldering.”