LG LCD TV problem

[groggycl]

Hi guys, just a question, some time ago my LG lcd went dark when I turned it on, it show black image with backlight and as time and audio from the tv channels is playing, lines of colours are displayed on the black screen but after some time (20 minutes or so) image magically comes up and it works beautifully. It always happen till this day. You turn it on, black screen with lines of different colours and 20 or 25 minutes later, image comes up and it would work for a day long no problem if you don't turn it off. I thought, I will use it until it dies, but it still working 3 months later so I think it could be an easy fix, please help me

 

[JayCee]

It's an easy fix if you can solder and can handle electronic components.
It's probably duff electrolytic capacitors in the power supply circuit...these are the no 1 suspect for any fault symptoms which clear after a warmup period on electronic equipment.

 

[groggycl]

Well, I can solder electronics... I am a very DIY guy, well I will give it a try. I am taking apart my tv hopefully tonight, and take a look at the electrolytic capacitors and tomorrow see if I can get parts. Then I'll try replacing them.

Question, how many should be there? how can I know wich one(s) is deffective, so I don't have to replace all of them? (multimeter, try resistance and look for a 1 number?

thanks man!!

 

[JayCee]

Identify the power supply section which is usually on a separate pcb and look for swollen tops on the electrolytic caps...a multimeter won't be any use.

Sent from my iPad using AVForums

 

[groggycl]

well I finally opened it and see no badly faulty capacitor... there is one that its cap seems not to be as flat as the others, may that be the bad one?

I took a high res picture, please help me I forgot to mark the one I suspect but it is the smallest of the group of 5 that is at the bottom left side of the picture.

Thanks!

 

[GGTVBD]

That one does look sus.

Model number of the set?

 

[groggycl]

The set its a LG 26LG30R-MA.

GRUMPY, do you agree that that small one may be the faulty one?

 

[JayCee]

The set its a LG 26LG30R-MA.

GRUMPY, do you agree that that small one may be the faulty one?

I concur with GOT...it does look suspect and is certainly the first one to replace.

 

[groggycl]

ok, I think this pieces should be inexpensive, I'll take apart the tv tomorrow, check the piece and go buy another one, I will post how it goes,

thanks everyone!!

 

[GGTVBD]

Let me know the value and I'll pop you one in the post, FOC.

 

[groggycl]

well, ten years later, xD, I replaced the capacitor. It was a 220uF 25v one, but the problem wouldn't fix. I read that capacitors can look normal an still be failing...

I have no problem replacing all of them but I wanted to ask if, in your experience, this problem I have sounds definitively like a capacitor problem?

the other question, the power supply board have two sides (primary and secondary), should I replace just the secondary one? in the primery side, there are 2 big capacitors, I read that those rarely fail, should I replace those also? or just try with the little ones?

Thanks again!!

 

[groggycl]

well, I went ahead and bought a repair kit as I was having trouble getting a couple of the electrolytic capacitors here in chile..

I changed all the capacitors except fot the two big one, they weren't included in the kit and the seller said that those would greatly increase the cost and those very very rarely fail.

Anyway, I changed them and tv still the same, 5 to 10 minutes to show image, any other sugestion folks?

thanks!!

 

[GGTVBD]

Many LG models also suffer from main PCB faults which cause many weird picture symptoms. There is an official (UK) mod for these which is quite involved and involves removing and linking out lots of surface mount components. Not easy!