LG 37LC46 power on problems

[clarksters]

Hi, new member hoping someone can help.
I've an LG 37LC46 which recently started taking longer and longer to start up, I had a search and thought it was the power board that was at fault, I opened the tv up to inspect the board and there were obvious bulges on several of the caps. So I bought this board on ebay, I fitted it today, it resolved the power on problem i.e. powered on straight away, but within a few seconds of powering on the screen would go black and then the TV would go into standby again. On comparing the boards there are slight differences in the old power board and the new board.
At the minute I'm a bit lost for what to do next, in my mind the new board either faulty or not the correct board for the TV, or perhaps the TV needs a firmware update to work with the later version of the board?
Any help would be greatly appreciated, thanks.

[whatusername]

Re: LG 37LC46 power on problems

return the board you bought back to eBay and on your old board just replace the capacitors that are bulging. you can get them from digi-key relatively cheap anywhere from 80 cents to a 1.50 depending on da size

[clarksters]

Re: LG 37LC46 power on problems

I genuinely don't think I could change the capacitors myself without doing more damage, I don't have a soldering iron either so buying a replacement board isn't that much more expensive.

[clarksters]

Re: LG 37LC46 power on problems

Ok, I've refitted the old board and managed to get the TV on with it, but it's now also showing the same problem of the tv turning on then turning off seconds later, so it looks like the new board is ok, but there's a new problem with something else.

I should also add the original issue with the tv not turning on got worse during the week to the point where the tv wouldn't even get into standby.

[Crrose]

Re: LG 37LC46 power on problems

I have same problem with my LG32LX1D, Not sure what your board looks like but after much research and help on this forum I narrowed mine down to capacitor #C126. I unplugged the power and heated it up with hairdryer for about 2 minutes, plugged tv back in and it powers back up. It only stays on for a few minutes but I think all I need to do is replace that capacitor. Worth a shot if yours is the same.

[selldoor]

Re: LG 37LC46 power on problems

@crosse - Yes that was probably his original problem - he doesnt do soldering - so he bought a new board. Now seems to have another problem.

[clarksters]

Re: LG 37LC46 power on problems

Yes, I used a hairdryer to get the old board to work and the tv still displays the problem of powering on the screen and then turning off after a couple of seconds, I really don't want to scrap the tv, but I'm at a loss for what to do next.

[tom66]

Re: LG 37LC46 power on problems

So screen light up for about 2 secs then goes blank? The inverter boards on this are a common fault.

[clarksters]

Re: LG 37LC46 power on problems

Yes, screen lights up for a second, goes blank then after another second the tv goes into standby.

[tom66]

Re: LG 37LC46 power on problems

Does the power light go red, indicating standby? Also, does the sound stop? Have you checked the side buttons to see if any are stuck down or jamming?

[clarksters]

Re: LG 37LC46 power on problems

I plug in the tv
The red standby light comes on
I hit the power button and the green light comes on and the screen appears
After a second the backlight goes out and the screen goes blank
After another second the tv goes back into standby and the green light goes red

I don't think any buttons are jamming because only the power button would turn the tv off, right? And the tv isn't stuck in an on/off loop.

[tom66]

Re: LG 37LC46 power on problems

I had a TV that treated a partially depressed power button as "Turn off randomly when you feel like it." I would first, as a matter of course, attempt to clean/inspect the side button board and check all appears to function.

[clarksters]

Re: LG 37LC46 power on problems

I disconnected the button board, the problem is still there.

[clarksters]

Re: LG 37LC46 power on problems

Any more suggestions are greatly appreciated.

[vinceroger69]

Re: LG 37LC46 power on problems

to to recap as per post 4 are you still using your old original board with bad bulging caps on? if thats the case you need to check the caps and replace any that are bulging or have high esr/out of spec.

[clarksters]

Re: LG 37LC46 power on problems

Both new and old boards now display the same fault. I bought the new board because the TV was taking longer and longer to switch on. I can get the old board to switch on again if I heat the caps with a hairdryer, the TV switches on immediately with the new board, but the TV has the same fault of switching on for a couple of seconds then off again with both boards (this was not the original fault that prompted me to buy a new board).

[vinceroger69]

Re: LG 37LC46 power on problems

can you post a good clear picture of your power board imo it does seem like a bad capacitor issue but post a picture of the psu board and also by the connectors so we can see what the voltage markings are printed on the board have you got a multi meter to test voltages etc we can advise you how to test them if needed.

[clarksters]

Re: LG 37LC46 power on problems

Images added, the first two are the old board with quite a few bulges, the second two are the new board.
I don't have a multimeter, but I could probably get one if someone wants to give me an idiot's (and I do mean idiot's) guide of what and how to test.

[hienton2]

Re: LG 37LC46 power on problems

Two left power board pictures have bad caps. Replace c221 ,217, and the one
next to 2 small green caps.(2200uf). Those caps look bad to me.

[clarksters]

Re: LG 37LC46 power on problems

Why would I be having issues with the new board though? I bought the new board because the old one had bad caps and was taking a while to turn on. The new problem is it now powers on, the screen comes on and then goes off again after a second.
I can heat the caps on the old board with a hairdryer and replicate the same problem with it. This is a new fault that wasn't previously present in the old board before I replaced it, but is now happening on both.