Our 7 year old LG Flatron 32" old school, fat, super heavy, proper TV has just started to randomly turn itself off.

Anyone experts out there know if it is a common falt or easily repairable fault ? or is it bin fodder ?

We know we should really get one of those flashy wall mount jobbies but we love the tele, it fits in our lounge alcove perfectly and quite frankly, we are skint

Also, it weighs about twice as much as i do and dont fancy getting out of the lounge (on the 1st floor) and doing myself an injury...

I presume a local repair company will cost more than its economical to pay ? i work in instrument service so am not afraid to pull it apart and try myself if anyone has any ideas ?

Regards Andy

try giving it a bit of a dust down in the back and a hoover, but dont touch the capacitors

someone suggested that but it sounded a tad too simple, not that i have a clue though, if i can find a crane to get it off the stand i will try that first then, im liking the cost free option

I have heard the capacitors are pretty dangerous !

No first hand experience of this particular model, but check all the solder connections on the PCB for dry joints - especially around the LOPT (the chunk with the thick wire that goes to the side of the CRT tube).
Dusting and hoovering will certainly help if it's an overheating issue.
The capacitors can be dangerous as they can have aroun 380volts across them. Unplug it from the wall, and wait about a minute before touching anything just to be safe.

when i worked in a photo lab, we used to charge the flash up in disposable cameras, pull the capacitors out, then catch one of the guys off guard shouting 'catch!' and throwing it at him, he'd turn round and catch a fully charged capacitor. you get a nasty shock, and thats just from a battery.

so yeah, watch those capacitors! they'll hold a charge for a while after the tellys switched off

bet it will be a dry joint ,i would bin it as its now a real fire hazard ,im a x-granada repair man cst.
my brother repair plasmas and lcd (im lost when he shows me stuff,but its all plug and play now)

quote:

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Originally posted by austin man
try giving it a bit of a dust down in the back and a hoover, but dont touch the capacitors

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You can get a small TV repair manual this lists common faults (most of them are common) with certain makes/models, Ive got a copy in the office somewhere, I'll try and dig it out for you tommorow, although I dont know how old my copy is.
Sounds like a duff capacitor in the power supply to me.
Cheers,
Bob

I did a little TV repair work during my apprenticeship, but it was a long time ago, so this is more generic advice rather than specific to the set you have.

First off, TV's contain some very nasty voltages so treat them with the upmost respect. It's not the capacitors you need to worry about. Although some are probably charged to mains voltage they will discharge quite quickly if the set is left switched off for a while. It's the tube itself that holds charge, and you should discharge it before poking around. I've had a belt off a 24" Sony before which, to put it mildly, wasn't pleasant. There's far more surface area on a 32" which will make it worse!

The way I was taught to do this was to first check that the mains plug is wired correctly (ie that live and neutral havn't been swapped). Then plug the set in, switch any hard power button on, but leave it switched off *AT THE WALL*. That way you have a good ground on the chassis but no power to the set.

Make up a decent thickness cable (the sort of thing you'd wire up headlights with on your Locost would be good) with a crocodile clip on each end. Clip one end to the metal chassis inside the set, and the other to an old flat blade screwdriver.

On top of the tube (that's the big glass thing inside in case you didn't know!) there will be a rubber cap that looks like the sort of thing you'd attach a sat nav to your windscreen with. Underneath is a metal connector that mates into a lug, which in turn connects with the coating on the inside of the tube. Slide the flat blade of the screwdriver under the cap so that it touches the connector, which will discharge the tube. Obviously, hold the handle of the screwdriver, not the metal! You'll probably hear a crack as this happens. Leave it 5 minutes, then repeat. Do this 3 times to be sure, waiting 5 mins or so between.

The unplug the set and leave it whilst you make a cup of tea, which should be long enough for the capacitors to discharge.

Even then, be very careful when you poke around inside. TV's attract all sorts of dust and carbon out of the air which can be conductive, meaning you can still get a belt even if you're not touching anything metal. I can't stress this enough - TV's are very dangerous things for an amateur to mess with!

Anyway... as for the fault, if the set is randomly dropping to standby the usual problem is that the over current protection on the heaters inside the tube is being tripped. Over time, bits of the carbon coating on the inside of the tube will flake off and get attracted to the heaters due to the charge that is placed on them, which causes small short circuits across the coils and increases current flow. The tube is sealed, so there's no way to clean them out.

The best thing to do in this situation is to gentley tap the neck of the tube as far back as you can with a screwdriver handle which should hopefully dislodge them and make them drop to the bottom. You might also want to try tipping the set forward whilst you tap it to encourage them to fall out of harm's way.

This is not an ultimate fix, and of course it may not be the problem in this case, but it should buy you another year of life out of it.

Have fun, and **BE CAREFUL!!**

Chris

[Edited on 4/15/2009 by ChrisW]

one obvious thing to check is the battery’s in the remote. I know mine goes nuts when low and the tv then misbehaves including switching on and off by itself

Just to add to ChrisW's suggestion, there's no need to plug into the mains. TV's haven't used an earth wire for donkeys years, so it will have no effect. As for discharging the CRT, Chris's method is correct. There may be charged capacitors in there especially if the flyback transistor or transformer has gone open circuit - no discharge path. However, as this is a random sort of event the transistor / transformer seem to be ok. The fault would point to a dry soldered joint around the high voltage side (2 components above most likely).
I wouldn't tap the tube base as it's all too easy to break something.

Cant find my TV fault finding guide, the flaming thinks been staring me in the kisser for ages, found my VCR fault guide no problem....dont you just hate it when this happens.
Cheers,
Bob

Wow - some fantastic advice, im thinking i will leave it turned off until my dad comes up next weekend, he used to fix tele's in the olden days !

Seems sensible to have some help from someone that will atleast know what he's looking at,

Cheers for the info..... Andy