PCB/dry solder joints repair?

[L00b 441]

Our TV started misbehaving yesterday, HDMI channels have ceased to work (not connecting to any source). TV works fine with DVB/Freeview, it's literally just the HDMI inputs that have gone on the blink (unfortunately I can't test the YPbPr and AV inputs, haven't got anything to test that with).

 

After leaving the thing unpowered (and disconnected from mains and aerial) for an hour, then resetting the thing to factory default, and many attempts trying different combinations of alternative sources and HDMI inputs, still no joy.

 

Research online suggests that many LG TVs manufactured in 2010/2011 (which ours is) came to suffer from the same issue around 2015 and, with owners reporting some success at a DIY repair involving a 10-minute oven session for the PCB, that to me spells 'dry solder joints' and the oven effectively carrying out an artisanal reflow.

 

I'm a bit miffed considering that, alright it's 7-ish years old and has given good service all along, but it was a flagship model at the time. Dry solder joints, I'd expect on no-name or low-end models, not on top of range kit

 

As a curveball, it seems to have occurred around the same time as we suffered a brown-out (we discovered, on coming back from a walk, that the oven timer function was off/non-functional, very odd; a hard reset with the oven mains cured that), so it may not be dry joints after all. But then, if the brown-out damaged the TV electronics (somehow, as TV would have been off at the time), could it be that it only knocked the HDMI section of the PCB? I'm doubtful.

 

Anyhow: I can dismantle most electronics and safely take components out, and put things back together again alright, but I am a bit dubious about that DIY method (and don't fancy kackering the oven -which is a year old- or starting a house fire ), so does anyone know a reputable repair place in Sheffield for PCB diagnostics (and dry solder joints fixing, if that's the issue)?

Edited June 6, 2017 by L00b

[mafya 243]

There is a place on Attercliffe road called Nova electronics that have been about for years who repair electronics, it might be worth giving them a call= http://www.nova-electronics.co.uk

[apelike 10]

Have a google as it may be a lot cheaper to buy and fit a replacement board as they seem easily obtainable depending on model.

[alchresearch 214]

There is a place on Attercliffe road called Nova electronics that have been about for years who repair electronics, it might be worth giving them a call= http://www.nova-electronics.co.uk

 

It was my brother who did all the repairs - did loads of TVs. But he's moved on now, so I'm not sure if they still do it. But well worth a call.

[L00b 441]

There is a place on Attercliffe road called Nova electronics that have been about for years who repair electronics, it might be worth giving them a call= http://www.nova-electronics.co.uk

Thanks much mafya, I'll bear them in mind

Have a google as it may be a lot cheaper to buy and fit a replacement board as they seem easily obtainable depending on model.

LG 47LE8900, looks to include several boards (main and daughters): there's one same TV currently FS on eBay atm (as spares/repair) and the seller's description suggests that it's a daughter board which is in charge of the inputs (-being the faulty part, as described to him by a repair engineer). Sounds like my problem, although his description of the symptoms (distorted picture) doesn't sound like mine at all.

 

I'd really need a service manual with diagnostic flowcharts, before wasting money buying this and that other board, and can't find a free one online so far

Edited June 6, 2017 by L00b

[Ghozer 112]

It's quite easy to fix dry solder joints....

 

the time comes from stripping the TV down to get to everything, and re-building it...

[zach 234]

I don't know L00b, it's only a guess.

 

Have you had to back off and checked if that board has power to it, or a fuse that's blown?

 

I'd check the cables too. give them a re-seat.

 

I just had a look round for a service manual but no luck there. For all ports to go at once it could be a re-flow option but I doubt it.

 

Good luck with it and if I find anything else, I'll let you know.

[jay ov s2 10]

hi Loob

 

not really into tv's but have had quite a few lg tvs most recent ones suffered with sound but no picture on hdmi which I was told was 1 of 8 mosfetts on one of the boards unsure which one.

 

Also my friends lg hdmi ports stopped working altogether was told by tv engineer that the ports had locked and would be £80 to repair/unlock in the end he decided to buy new.

 

Thanks

 

Jay

[L00b 441]

Not had a chance to take the TV off the wall and have at it yet I'm afraid, professional and family commitments continually getting in the way.

 

I was going to do that last Saturday (full AV setup strip and reinstall first, device by device, then screwdriver time if that fails), but did a further, last-chance-saloon factory reset just before, and what do you know, after that reset and autotuning, the HDMIs were worked fine again: BluRay and WiiU through the AV amp, sound and pic, no apparent problem.

 

Went to fire up the WiiU again sometime on Sunday to check a Youtube vid, and bam! HDMI failing to connect again (you can see the 'connecting...' in the HDMI channel icon for 3 seconds or so, as soon as you switch to it, but then it goes and stays 'No Signal'). So I tried a couple more factory resets again, but no joy.

 

'Port locking', if such a thing exists (and is not just the TV engineer code for easy money flicking a switch ), could be a possibility: after the brown out, as I did not know if it was a factor or not, I disconnected and reconnected my Raspberry Pi, first in the TV, then on a spare HDMI input of the AV amp. So maybe the 'HDMI encoding bit' in the TV got its electronic knickers in a twist? Not sure why the things would stay locked after a full power down with unplugging then a factory reset, though. [EDIT: can't be that, since the HDMIs started working again last Saturday - duh me!]

 

All of the kit (BluRay, WiiU, AV amp, Pi) works fine through HDMI on another TV, so they're ruled out. And that's using the same HDMI leads as connected to the LG TV (disconnected master lead from AV amp to LG TV, connected into spare TV), so it's not the leads either.

 

Anyhow, more to follow, prob. next week (weekend is solid, no chance of getting anywhere near).

Edited June 15, 2017 by L00b

[jay ov s2 10]

 

Also my friends lg hdmi ports stopped working altogether was told by tv engineer that the ports had locked and would be £80 to repair/unlock in the end he decided to buy new.

 

Thanks

 

Jay

 

Possibly a posh word to say the hdmi ports are naft and maybe he was going to change one of the boards.

 

Jason

[Jerky 10]

Lg are not good.I wouldn't touch one. They may look great and have a decent reputation but i really dont why. Perhaps good marketing.Missing pixels, sluggish menu, ports failing are the most common complaints but they have high failiure rate compared to sony,samsung,panasonic and hisense.