LG OLED TV turns off after few seconds FAQ

Fixing modern SMD electronics requires a hot air reflow machine, a microscope, an infra red camera lots of flux, low temperature solder, an accurate soldering iron and very steady hands.

Sometimes its possible to spot the bulgy capacitor spewing its guts out. But no one supplies circuit diagrams at all. And many chips are custom made for the manufacturer and are not available as spares. If you can cannibalise another non working set, that's good.

If you want to invest ion a couple of thousand quids worth of board repair kit or pay someone £60 an hour to try and fix something that's not worth £50...and have no guarantee it will subsequently work, be my guest.

The long and the short of it is that modern consumer electronics - and even industrial electronics - has limited repairability. Its just about worth fixing a £1000 smart phone or laptop, but not a TV that you can probably get in Currys for £80...

Unfortunately, that is indeed the way of the modern world. A shame, a great shame, in my opinion. How much stuff is wasted because of this?

When I was still working, in industry, it was even more true of industrial than domestic equipment.

I am sure back in the day people were bemoaning that it took thousands of pounds of equipment to repair a vacuum tube. And you just had to throw them away.

And then the problem with these integrated circuits was that you just couldn't repair them. You had to throw them away.

Well today the printed circuit BOARD is a component...that you just 'throw away'. Mostly.

Was it? I would have thought the opposite.

snip

If it's less than say 5 years, I'd try it on with the retailer. OLED and LG is supposed to be 'premium', and I reckon you could make a half decent case if it isn't too old.

Quite pleased/surprised to find that Richer Sounds gave a 6 year warranty FOC with my LG OLED.

As I remember it, the Consumer Rights Act 2015 (and EU legislation), had the concept of "reasonably durable". I think for many long life items, this was six years. So Richer Sounds may just have been recognising a default consumer right.

I think a modern TV should be expected to last 6 years. Worth contacting LG.

Broadcast TV, avionics and medical is still worth repairing, due to the astronomical cost and the unwillingness of customers, who are relatively few and have a great deal of spending power, to accept hugely expensive goods which are unrepairable.

Even so, I have written off three camera control panels, which are pretty much a single PCB which contains... wait for it,,, a *400* pin IC. This is obviously a ball grid array, and the slightest flexing of the PCB will break a few joints, and even the factory will not offer an economic repair.

Even worse is stuff which isn't broken, but has no practical use. On my dining room table is an HP business computer, has Win10 but can't do Win11, and in a few months it will be useless to Windows users like my wife. It's only about half as powerful as my current HP desktop, so it's of use to me only as a backup. If the only alternative is literally throwing it away, I might keep it for that.

Block diagram. No indication of a four pin TTL level debug header.

The interface controls appear to be a subassembly in the lower right corner of that diagram.

A Google shows as many firmware reasons for failure, as hardware ones.

An HDMI cable can short out the +5V. An HDMI cable can also receive a command via CEC, to shut off.

Paul

Thanks very much for the info Paul. Unfortunately it does this without anything connected to the TV although maybe something shorted it which fried something?

Seems a shame that there is no way of troubleshooting the master board so either you buy one on the off chance it might be that or bin the TV I guess. Since there is a green line appearing when it starts to turn on I wonder if this is an indication that it is the panel?

Depending on how old and what processor /motherboard you could try this:

My guess, the power supply is not giving the full beans current, and instead is going into fault mode. Full beans may not be available due to charge failing capacitors on the secondary side of the switch mode supply, which can be checked with a ESR meter. Or you may have other capacitors failing short - freezer spray, thermal imaging camera?

There are a few youtube vids around on diagnosing TV faults, but you probably haven't time to watch them all. However, try your hand at writing a prompt for an AI to help diagnose it.

"I have an LX xxxx TV to fix, the power led only lights for 5 seconds. What should I look for in the power supply. Can you show me part references"

When I just tried this, it came back to me with a question

Do you already have the TV opened? (If yes, you can tell me the PSU model number — it's usually printed like "EAYxxxxxxx" or "BN44-xxxxxx."

Then you get specific stuff like

"Most common failure points on BN44 boards (which are made OEM by Samsung....)

QP801 or QM801/QM802 (Shorted FETs)

DP801/DP802 (shorted Schottky rectifiers)

Startup resistors near ICU801S

Bad optocoupler PC801S

Capacitors bloated or high ESR

Cold solder joints, especially at transformer pins and diodes

Quick First Tests You Should Do: Step What to Check Expected Result

And there the rabbit hole descends into a sort of hell where wild geese are out for you to chase...."

You can ask it to make a trouble shooting flowchart, point out a youtube video for the PSU, find a schematic etc....

I was thinking of something like that, also possibly thermals. I have a Philips monitor (BDM4065UC) that'll run for half an hour, then shut off. If you power cycle it it'll run for 5 minutes then shut off, if you repeat it gets down to 2 seconds. I bought a spare with a cracked screen and swapped the PSU board, same problem. Next stop is to redo the thermal paste on the heatsinks and try again - but disassembling/reassembling the thing is a PITA.

For Lee's I'd probably try putting some series resistors in series with the power rails and scoping the current draw. Maybe you can catch a current spike? Or watch the voltage sag and then shut down as the CPU gets a power-bad message and bails out.

I wouldn't put a whole lot of store by what's on the screen - normally you need the timing controller (TCON) to be fully booted before you can expect to see anything. On an LCD you can see if the backlight comes on, but there isn't a backlight on an OLED panel.

That seems like plausible-sounding gobbledegook. Yes certain boards have certain faults which are known about in repair forums, but every board is going to have different component IDs - it's unlikely the optocoupler is PC8015 on every single one. It's likely to make the problem bigger because now you're looking for things which don't exist on your board.

If I search for BN44 I find a ton of repair information including people selling repair kits, which didn't need any AI. If a search has not pulled up information about repairing Lee's board then I'd not expect an AI to contribute anything useful - I expect it just to add a big waste of time. But I would do some searches over board IDs as it's quite possible that searching by model number may not have matches.

I suppose the AI could be useful if you aren't good at searching...

Possibly for generic stuff, but for specific stuff where little detail is available, I expect it'll just make stuff up. And where you had one problem, now you have two.

Theo