LG TV: image = No. sound = Yes

[snuf]

Hi Everyone

I hope this is the right place to ask this question - if not I will be happy to get suggestions where should I post this question

I have an LG 43UK6300 TV

After 2.5 years of use, the image disappeared all of a sudden but I can hear sound (even the sound that comes from my PC /HDMI)

I want and I will repair it myself. But I need a small advice.

I baked the motherboard at 200 degree in the oven for 10 minutes (Utube Video) and the only result: I feel dumb - it didn't helped.

My next step: buying a Multimeter for checking the LEDs

I never worked with one. Will this do the work?

https://www.amazon.fr/Multimètre-numérique-AstroAI-amplificateur-tension/dp/B01ISAMUA6?ref_=ast_sto_dp

*If anyone have a suggestion / other step that I should follow - I will be happy to hear

*Should I check also other components with the Multimeter?

 

[ProDave]

Probably LED's or the driver.

Try registering and asking here https://quuq.org/forum/index.php?board=24.0

About the only free tv forum I know.

 

[Andy™]

just use it as a radio

 

[Geoff1946]

The meter looks OK for general electronics fault finding.

I've never heard of baking a board before! Hair dryer and freezer spray for locating thermal faults, yes, but 200 degrees sounds a bit drastic to me and I would especially worry about plastic parts.

Anyway, good luck.

 

[Bruspark]

Any reset you can do without using a on screen menu is worth checking, as are any brightness controls that might be turned down
Any trace of a faint but un-illuminated picture is worth investigating further (backlights can be repaired fairly easily)

Ignore the bad advice on YouTube on almost every subject.  Also,  If something simple takes 20 -30 minutes of waffling with adverts and loud backing music I'd ignore it  . . 

Without a manual for the TV you'll have no idea what to look for or where, or what to do with your meter and so will probably blow it or yourself up even it survived the oven (!!!) . . .

With a Manual, for most faults, it's still too complicated/risky to call DIY   (see https://masterelectronicsrepair.blogspot.com/2020/09/repairing-servicing-tv-lg-43uk6300.html)

Without spending more on exchange parts and test gear than the set will now be worth even if fixed  I'd say work through any common user-error fault postings you can find online and then be  prepared to give up.

 

[Bruspark]

The meter looks OK for general electronics fault finding.

I've never heard of baking a board before! Hair dryer and freezer spray for locating thermal faults, yes, but 200 degrees sounds a bit drastic to me and I would especially worry about plastic parts.

Anyway, good luck.

It's usually touted as the only DIY way to deal with poor solder joints under big flat BGA (100's of solder ball connections underneath ) IC's like Graphics chips, processors and soldered memory etc.
Some Apple laptops were famous for this problem and some boards reportedly did get fixed this way.   I guess those who destroyed their board usually didn't post the results on you tube though . .

A bad joint in lead-free solder, with no new flux introduced is most unlikely to fix itself at 200C anyway but plenty of other components may be displeased after a while at 200C.   DIY success rate therefore pretty small but try if you must . .  

Correct approach is to
Use known fault lists /mechanical force / or as last resort electronic diagnosis to identify the problem areas /item(s)
Remove the suspect chips with a hot air or IR re-work station, without damaging the board or affecting other nearby components (very easy after a few 100 hours training /practice  )
Re-tin the board, clean off and re-flux the IC and replace using hot air /IR again, reaching a temperature more like 350C .     Use localised heat at all stages

After all this it may work, or the chip may have failed initially rather than had a bad joint.   (Hence preferring known faults and  mechanical force that 'wakes it up working' to diagnosing the fault area electronically which provides no evidence the chip is still ok.   The board rarely survives a second removal to dfit a new Chip . .

Mentally tell yourself this work is worth £100 per hour and you'll find board swaps or chucking it out seem a lot more sensible in many cases, especially if no one will pay you £100 per hour to not fix something  

 

[Sharpend]

just use it as a radio

  :slap  the guys a genius! The new DAB radio!! Cant see it catching on though if I’m honest. 

 

[ProDave]

  :slap  the guys a genius! The new DAB radio!! Cant see it catching on though if I’m honest. 

A bit hard changing channel as it's all done with an on screen menu.

 

[Sharpend]

A bit hard changing channel as it's all done with an on screen menu.

No different to my Marantz stereo, have only got two radio channels as now all out the blue I’m have to subscribe to some third party site to get digital radio!! Not bad for a £500 stereo and that’s without speakers. 

 

[Andy™]

A bit hard changing channel as it's all done with an on screen menu.

just remember which buttons you need to press. but if its the same radio station then usually jsut need to turn it on and volume up/down. no need for a screen

 

[steptoe]

It will be the LEDs , 

I had an LG with the same issue, 

Try shining a torch tight to the screen and see if you can see any sort of picture.  

I can send you some LEDs if you want, I have some left over from repairing mine, 

You will need TWO soldering irons to solder both ends of the LED at the same time.

BTW , LG TV was the biggest POS I ever had, nothing but problems from day 1. 

 

[ProDave]

It will be the LEDs , 

I had an LG with the same issue, 

Try shining a torch tight to the screen and see if you can see any sort of picture.  

I can send you some LEDs if you want, I have some left over from repairing mine, 

You will need TWO soldering irons to solder both ends of the LED at the same time.

BTW , LG TV was the biggest POS I ever had, nothing but problems from day 1. 

Have they got any easier to repair?

I have only done a few and the ones I have done have required you to dismantle the panel, layer by layer to eventually get to the backlight strips.  The actual LCD glass panel on a large screen set that has the be lifted off in this process is remarkably fragile, and my success rate without damaging the panel has only been about 50%, so it is not something I would be in a hurry to try again.

Why oh why they can't make them with the back of the display panel removable to gain easy access to the LED strips without having to dismantle the panel beats me.

 

[Andy™]

Why oh why they can't make them with the back of the display panel removable to gain easy access to the LED strips without having to dismantle the panel beats me.

cost. no other reason

 

[steptoe]

Have they got any easier to repair?

I have only done a few and the ones I have done have required you to dismantle the panel, layer by layer to eventually get to the backlight strips.  The actual LCD glass panel on a large screen set that has the be lifted off in this process is remarkably fragile, and my success rate without damaging the panel has only been about 50%, so it is not something I would be in a hurry to try again.

Why oh why they can't make them with the back of the display panel removable to gain easy access to the LED strips without having to dismantle the panel beats me.

It was a few years ago I done mine, if you remember, it was you that actually gave me some advice on it.

And, as you say, I ended up with a small couple of mm line down the centre of the screen where I must have creased a connection or something. 

It was still useable tho, I ended up giving it to a young girl who was moving into her first flat.