LG TV Turning on and off constantly (trying to repair this)

[densmith123]

Re: LG TV Turning on and off constantly (trying to repair this)

I successfully repaired this problem on a TV for a friend. Please see my writeup at:

https://www.badcaps.net/forum/showth...925#post775925

[Steamy777]

Re: LG TV Turning on and off constantly (trying to repair this)

Ok figured it out replace capacitor c 216 worked for me

[lalease]

Re: LG TV Turning on and off constantly (trying to repair this)

Hi friends,
Try unplugging keypad assembly, from IR detector on/off assembly. Then try remote control, if problem goes away get new keypad or just don't plug it back in.

[Steamy777]

Re: LG TV Turning on and off constantly (trying to repair this)

You think thats it? I can't go back to the TV speciliast place as its been such a terrible experience thus far (some other snafoos too).

I'm tempted to just buy another used power board and give it a shot as I don't know where I'd get resoldering done - my local computer place said they won't do it.

I read up on some other threads and tried disconnecting all other power buttons in hopes there were some faulty buttons getting triggered - didn't work. Kinda narrows this down a bit more. It seems this on/off junk is a fairly common 52lg50 problem. Lots of other threads not finding too clear of an answer or the thread just ends. Buy a new board and hope for the best?

This guys issues are quite similar to mine and it looks like even LG didn't know wtf to do - http://www.justanswer.com/tv-repair/...september.html

Hi does you tv have any picture when it goes off and on if no its your t con board shorting had the same tv same problem.

[bammbammfran]

Re: LG TV Turning on and off constantly (trying to repair this)

Cant believe I missed that - too busy looking at the brown which didnt look like overheating to me. I usually see cracked poor joints even when there arent any . Also whilst the back of the board is not too sharp a picture the joints look ok from that side.



Just checking - it was the main board he replaced and we are looking at the original power supply as being faulty.

I can actually see a pin hole on the back side.looks like the pin mostly just slid out

They had a said that the main was changed, so if they used the correct wording, it was not the power supply

Went back to first post and saw two mains in the picture. SO yes, main board

[selldoor]

Re: LG TV Turning on and off constantly (trying to repair this)

Have you checked those MOSFETs don't have cold solder joints?

Cant believe I missed that - too busy looking at the brown which didnt look like overheating to me. I usually see cracked poor joints even when there arent any . Also whilst the back of the board is not too sharp a picture the joints look ok from that side.

It is more than possible you got two boards with the same fault... sellers rarely test their pulled boards despite their claims of doing so.

Just checking - it was the main board he replaced and we are looking at the original power supply as being faulty.

[Andrew F. Ali]

Re: LG TV Turning on and off constantly (trying to repair this)

Agreed.....Buy a soldering iron and a roll of solder as suggested and try your hand you can do this.....just heat the work with the iron and then apply the solder and let it flow....Good luck

[bammbammfran]

Re: LG TV Turning on and off constantly (trying to repair this)

going back to them was more to be meant as a joke or to shove it in their face !!
It looks like that pin is lifting itself out of the board so it is a pretty good and likely suspect

Buy a soldering iron and some flux or borrow one from someone and do it yourself
if buying one , get a 45 or 60 watt one with a flat type tip

another used power supply may get the same issues .

[zsemago]

Re: LG TV Turning on and off constantly (trying to repair this)

take the board to that "TV Specialist" and have him resolder that mosfet

Inverter board look good

You think thats it? I can't go back to the TV speciliast place as its been such a terrible experience thus far (some other snafoos too).

I'm tempted to just buy another used power board and give it a shot as I don't know where I'd get resoldering done - my local computer place said they won't do it.

I read up on some other threads and tried disconnecting all other power buttons in hopes there were some faulty buttons getting triggered - didn't work. Kinda narrows this down a bit more. It seems this on/off junk is a fairly common 52lg50 problem. Lots of other threads not finding too clear of an answer or the thread just ends. Buy a new board and hope for the best?

This guys issues are quite similar to mine and it looks like even LG didn't know wtf to do - http://www.justanswer.com/tv-repair/...september.html

[bammbammfran]

Re: LG TV Turning on and off constantly (trying to repair this)

take the board to that "TV Specialist" and have him resolder that mosfet

Inverter board look good

[zsemago]

Re: LG TV Turning on and off constantly (trying to repair this)

It is more than possible you got two boards with the same fault... sellers rarely test their pulled boards despite their claims of doing so.

handoverface.jpg

[zsemago]

Re: LG TV Turning on and off constantly (trying to repair this)

Wouldn't the first step be to see what's happening with the voltages on the power supply when it's turning off and on?

I haven't done this because I don't have the tool to - probably next up to do. I really hope the TV repair guy I paid $90 to check out my TV would've done this cuz it sounds so simple.

[zsemago]

Re: LG TV Turning on and off constantly (trying to repair this)

The inverter boards appear fine. I think I have 4 of them? Below is a pic of 1 of the boards. No sign of burnage.

Another pic of the Mosfet thing too.

[bammbammfran]

Re: LG TV Turning on and off constantly (trying to repair this)

Hey tom,
YEAH !!
That one rivet looks bigtime messed up !

[fruitbat04]

Re: LG TV Turning on and off constantly (trying to repair this)

Wouldn't the first step be to see what's happening with the voltages on the power supply when it's turning off and on?

[tom66]

Re: LG TV Turning on and off constantly (trying to repair this)

I am referring to this photo, the drain leg of the uppermost transistor looks cracked at the board point. Could just be the angle or lighting but might be a sign of a cold joint.
https://www.badcaps.net/forum/attach...0&d=1403290307

[bammbammfran]

Re: LG TV Turning on and off constantly (trying to repair this)

Have you checked those MOSFETs don't have cold solder joints? They look really heated, which could be a sign of a poor or intermittent connection.

It is more than possible you got two boards with the same fault... sellers rarely test their pulled boards despite their claims of doing so.

that ebay board is not the OPs board
I posted it just to show them a common issue on these

[tom66]

Re: LG TV Turning on and off constantly (trying to repair this)

Have you checked those MOSFETs don't have cold solder joints? They look really heated, which could be a sign of a poor or intermittent connection.

It is more than possible you got two boards with the same fault... sellers rarely test their pulled boards despite their claims of doing so.

[bammbammfran]

Re: LG TV Turning on and off constantly (trying to repair this)

here is a good example of over heating where the yellow is tuning orange then brown
If you look at the bottom picture, you will see small black transistors in these areas. these are what parts a cooking

Looks you boards over to see if anything is showing signs of overheating.
Again I am thinking this because you said it flickered
This would normally not affect shutdown of a unit, but ???


http://www.ebay.com/itm/380746797819

[zsemago]

Re: LG TV Turning on and off constantly (trying to repair this)

I googled this and believe this is my inverter board? http://www.tvpartsguy.com/media/0f/a...6238ec2a_l.JPG

...I took the backs off of all my inverter boards and everything looks good. No bulging, no leaking. Is there something in particular I'm looking for? Could you show me some of the pics you're talking about regarding the "overheating" sections.

Is overheating a factor here? If the TV has been off for 24 hours and has trouble turning on. Once the TV makes it to on all issues are eliminated and the TV will act fine for as long as I need it. The initial turning on and turning it off are the only 2 areas where I have problems.