LG TV Switching On and Off

[RustySkull]

Hi, Let’s see if anyone can help us,

We have our LG TV which isn’t a smart TV, it’s around 10 years old and today started turning on and off by itself. It seems to be behaving like it’s not getting enough power, like a bad transformer for example. There is no transformer on the power lead though, if there is one it must be inside the TV.

It gets as far as the LG screen and displays the time, then goes off and does the same again.
If we unplug it, and leave it for a few minutes it might come on as normal, and be ok for about a minute before going off and doing the same again.
We have checked the plug on the TV and on the wall and they both seem ok.
No buttons are stuck on the TV or remote.

If anyone has any experience with TVs and can help that would be great 🙂

Many thanks,
Ben.

[electrofix]

will probably be the capacitors on the power board.
not an uncommon fault

Dave

[RustySkull]

electrofix wrote:will probably be the capacitors on the power board.
not an uncommon fault

Dave

Thanks Dave, do you know where I can get a schematic for LG TVs? LG maybe?

[electrofix]

model ?

Dave

[RustySkull]

electrofix wrote:model ?

Dave

Well Dave,
The only sticker on it is the serial number, 108WRVZ1J935

[RustySkull]

Hold on I’ve FK42LK450U, but LG don’t seem very helpful.

[RustySkull]

electrofix wrote:model ?

Dave

I’ve found a Power supply board on eBay for £12, I’ve ordered that. I was going to replace the caps but seen as a board is only £12, might as well change the whole lot…

[electrofix]

Lg wont be helpful. no manufacturer will give you this info. they are worried about getting sued if you hurt yourself

your model is correct if you miss the FK off the beginning
if you look at the pic of the power board i have arrowed the main output caps. these degrade over time. most of the time when they fail the top of them starts to bulge. so remove the back and check
beware the 2 large capacitors are charged at 300 volts and may not discharge. so its possible to get a shock off them even though its unplugged

Dave

[electrofix]

your board may be slightly different but its still the same caps you looking for
if they have gone you can replace the caps or get a second hand board off ebay from as low as £15

Dave

[RustySkull]

electrofix wrote:Lg wont be helpful. no manufacturer will give you this info. they are worried about getting sued if you hurt yourself

your model is correct if you miss the FK off the beginning
if you look at the pic of the power board i have arrowed the main output caps. these degrade over time. most of the time when they fail the top of them starts to bulge. so remove the back and check
beware the 2 large capacitors are charged at 300 volts and may not discharge. so its possible to get a shock off them even though its unplugged

Dave

Thanks Dave,
I took it apart to see which caps I needed and then put it back together, turned it on out of curiosity and it worked and seems to be working still now (Touch wood)

Perhaps dust was the cause… Who knows lol.

[electrofix]

unlikely will prob go again
got one at home doing it. turn it on and it goes off. keep doing it and after 5 mins or so it comes on and it ok for the rest of the day
but i must strip it and fix it

Dave

[Author]

Posts