Lg 55lv5500 - ta

[Cibby600]

Hi all,
New to the community and absolutely love what all you guys do.
I have a quick question before I start to troubleshoot further.
I was given this TV (55lv5500) that powers on, light goes from red to solid white.
No picture and no sound.
I got it apart and was removing the mainboard to start further testing and a possible reflow of the processor, and noticed the screws that mount the board to the chassis were very loose.
Does anyone know if these mounts are the main earth point for the board and will these making bad contact possibly be the cause of my syptoms?
Perhaps a clean and refit the board securely before I start pulling my hair out?
I have not tested any voltages etc as yet, just thought this might be worth trying first.
I have attached all relevant pictures, and pictures of the mounting points in question.
Thanks to all in advance. Bout to head out to dinner so will check the thread when I get home.
Cheers.
Cibby

[tw2005]

Re: Lg 55lv5500 - ta

You can be 100% sure it'll be the main processor. Any LG with it fai;s this way, Plasma, LCD, don't matter

[Cibby600]

Re: Lg 55lv5500 - ta

Cool. Thanks. I'll just reflow the processor then. Cheers.

[tw2005]

Re: Lg 55lv5500 - ta

Cool. Thanks. I'll just reflow the processor then. Cheers.

last one i tried I had partial success, then cooked it. Real shame because it would have been top of the range tv. Virtually every square inch is full of boards and speakers

[Cibby600]

Re: Lg 55lv5500 - ta

Well that didn't work.
Gradually heated processor area to 225c for about a minute, then slowly reduced temp for another minute to around 100c then let it cool to 30c before reinstalling board.
Cleaned all plugs and mounting surfaces with contact cleaner.
No change, power light goes from red to white but no screen. Power supply seems ok.
So, would any of you experts bother continuing to troubleshoot this, or would you pretty much bet its the mainboard and try and get a replacement?
I am willing to spend time narrowing it down, just not days. lol
Thanks in advance.
Cibby.

[dick_barton]

Re: Lg 55lv5500 - ta

The last time I read the cooking instructions were run up the heat slowly to 220C maximum, time 5 mins although I think the 5 mins may be a little too long. Then let cool down before removing it.

[Cibby600]

Re: Lg 55lv5500 - ta

Hi, yes, I pretty much did that. I think 1 minute at that temp should be enough, but I may be wrong.
I did it with a heat gun and a digital temp probe on my multi meter.
I am having trouble finding a mainboard online so I may have to troubleshoot this further.
Cheers.

[dick_barton]

Re: Lg 55lv5500 - ta

It would be worthwhile waiting to see what others who have been successful suggest.

[Cibby600]

Re: Lg 55lv5500 - ta

I will do. Thanks.
Found an authorised distributor of genuine LG parts in Australia with the board listed.
They want $400+ if its available!!!!!
I will wait and see what the experts chime in with as you suggested.
Cheers.

[tw2005]

Re: Lg 55lv5500 - ta

Something too, I have removed that BGA chip and the relays still click with the front LED changing from stdby red to white. Originally the backlight would at least turn on.

[Cibby600]

Re: Lg 55lv5500 - ta

Something too, I have removed that BGA chip and the relays still click with the front LED changing from stdby red to white. Originally the backlight would at least turn on.

Hmmmmm, so the chip could be dead all together?
I will start trouble shooting properly tonight.
Cheers.

[Nick's Tvs]

Re: Lg 55lv5500 - ta

There are some services on eBay for that main board that will replace the chip on the board if necessary. BGA rework is difficult and pricey, ($125 + $10 Shipping) but they will do a good job.

[tw2005]

Re: Lg 55lv5500 - ta

There are some services on eBay for that main board that will replace the chip on the board if necessary. BGA rework is difficult and pricey, ($125 + $10 Shipping) but they will do a good job.

And you could double that since we're in Oceania

[Cibby600]

Re: Lg 55lv5500 - ta

And you could double that since we're in Oceania

Was just thinking that! lol
I think I am going to troubleshoot as per other posts about this model and see how I go.
Might just chuck it on ebay as a whole for spares if I can't fix it.

Just got this reply from an authorised LG spares distributor in Australia:

"Hi Terry,
Thank you for your parts request.
MAIN PCB ASSY EBT61550301 P/N 1916467 has been discontinued by the manufacturer, all stocks are now exhausted and no substitute is available. Sorry but we are unable to supply this item"

Looks like I either fix it or trash it! LOL

[tw2005]

Re: Lg 55lv5500 - ta

Was just thinking that! lol
I think I am going to troubleshoot as per other posts about this model and see how I go.
Might just chuck it on ebay as a whole for spares if I can't fix it.

Just got this reply from an authorised LG spares distributor in Australia:

"Hi Terry,
Thank you for your parts request.
MAIN PCB ASSY EBT61550301 P/N 1916467 has been discontinued by the manufacturer, all stocks are now exhausted and no substitute is available. Sorry but we are unable to supply this item"

Looks like I either fix it or trash it! LOL

Can you take a really good image top and bottom, include any numbers, labels , PCB number etc

[Cibby600]

Re: Lg 55lv5500 - ta

Can you take a really good image top and bottom, include any numbers, labels , PCB number etc

Will do. I'll get back to you shortly.

[senndogg]

Re: Lg 55lv5500 - ta

If the chip overheats in seconds for sure it is faulty, very common. For reflowing i would recommend using a usual cooking plate as a preheater, cover any connectors or sensitive components with alu foil and start gradually rise the temp. when the pcb reaches 150' you can reflow at 230-240 for 2-3 minutes. Dont forget rma 218 quality paste. Reballing is another story, if you dont have a new (or known working) chip , all that job is pointless, reflowing will do just fine.

[Cibby600]

Re: Lg 55lv5500 - ta

Have attached pics of top and bottom halves of the board and a sticker that was on it before it shriveled up whilst I was attempting to reflow the processor.
And the serial off the back of the TV for good measure! lol
Cheers.

[Cibby600]

Re: Lg 55lv5500 - ta

If the chip overheats in seconds for sure it is faulty, very common. For reflowing i would recommend using a usual cooking plate as a preheater, cover any connectors or sensitive components with alu foil and start gradually rise the temp. when the pcb reaches 150' you can reflow at 230-240 for 2-3 minutes. Dont forget rma 218 quality paste. Reballing is another story, if you dont have a new (or known working) chip , all that job is pointless, reflowing will do just fine.

Have tried twice now with a heat gun and temp probe for my multimeter. Second time got to 235c for just over a minute.
I think either the chip is toat or something else is wrong.
Still powers on, light goes from red to solid white. Nothing else happens. No picture and I THINK still no sound.

[attainteddragon]

Re: Lg 55lv5500 - ta

i'm a little curious, you stated that the stby light changes states when you press the power button. what are the voltages on the connector that goes from the ps to the main, in stby and when you power it up. also list pin numbers and pin description, so it is easy to read.

at this point, you have not confirmed that it is a main issue.