Lg 55lv5500 - ta

[Dannyx]

Re: Lg 55lv5500 - ta

Yes, I concur: some readings from the power supply would be a requirement at this point. Also, you might want to test that PSU individually: the 5v stand-by pin should be jumpered to a PSU_ON or something like that pin. At this point, the board should come on and you should have the proper voltages at the corresponding output pins (5v and 12v) and also around 380v on the mains capacitor (provided it has a PFC boost circuit which I believe it does).

[Cibby600]

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.

I didn't get a chance to start checking voltages last night. Hopefully will get to it tonight and report back.
Thanks.

[Cibby600]

Re: Lg 55lv5500 - ta

So I have checked voltages on the 12 pin plug on the power supply board and the main board in stand by and then switched on.
The attached pictures have the Stand By voltages on the left and the Power On voltages on the right. Those left blank have 0V.
Looks like it is not sending or receiving the 24V power on???

Note: Back lights do not come on either!

Can anyone with more experience chime in.
I am a beginner hobbyist! lolol
Cheers.

[Dannyx]

Re: Lg 55lv5500 - ta

Voltages seem within spec. My 2 cents at this point is that the main board is faulty indeed.

[attainteddragon]

Re: Lg 55lv5500 - ta

so nothing on inv on and dimming pins, and nothing on the error pin?

off of the top of my head, you mentioned that you had backlights at some point?

[Cibby600]

Re: Lg 55lv5500 - ta

so nothing on inv on and dimming pins, and nothing on the error pin?

off of the top of my head, you mentioned that you had backlights at some point?

Not in stand by, no, and nothing on the error pin at all.
And no, I don't recall ever having back lights. Same symptoms from day one.
Cheers.

[Dannyx]

Re: Lg 55lv5500 - ta

Not in stand by, no, and nothing on the error pin at all.
And no, I don't recall ever having back lights. Same symptoms from day one.
Cheers.

Jumper those 3.5 standby volts to POWER ON and the PSU should come on (you should get consistent 12 and 24v). I believe this already happens, so next (with the PSU still on) try applying 3.5 to DRV_ON too and the backlight should come on, just to rule it out. It doesn't matter too much at this point if the backlight is working or not AFAIK....

[attainteddragon]

Re: Lg 55lv5500 - ta

np, you definitely have a main problem then. jump the ps on like danny said, just to confirm backlights and panel are good.

[Cibby600]

Re: Lg 55lv5500 - ta

Thanks guys.
Will try jump the 3.5 to DRV_ON and see what happens.
Just to be clear, can I just power the TV on, then jump any 3.5V to the DRV_ON pin on the mainboard?
Thanks. I am still learning!
After that I will try and reflow the IC401 and 402 chips as mentioned in another thread. I have nothing to lose.
I only concentrated on the main processor the first two times.
Cheers

[Cibby600]

Re: Lg 55lv5500 - ta

OK, think I have done some damage now.
I turned the tv on with the remote, then jumped one of the the 3.5v stand by pins to the DRV_ON pin on the PSU.
It sparked and the TV turned off and now the stand by light is solid white and it wont turn on now.

[Dannyx]

Re: Lg 55lv5500 - ta

OK, think I have done some damage now.
I turned the tv on with the remote, then jumped one of the the 3.5v stand by pins to the DRV_ON pin on the PSU.
It sparked and the TV turned off and now the stand by light is solid white and it wont turn on now.

You're supposed to disconnect the main from the PSU whenever you're jumpering stuff for testing purposes - the goal was to get the PSU to turn on without the main board...perhaps it was our fault also for not being very specific. You probably killed the CPU since a solid power light that doesn't react to any commands usually means a shorted CPU....have seen it happen a lot on TVs.

[Cibby600]

Re: Lg 55lv5500 - ta

You're supposed to disconnect the main from the PSU whenever you're jumpering stuff for testing purposes - the goal was to get the PSU to turn on without the main board...perhaps it was our fault also for not being very specific. You probably killed the CPU since a solid power light that doesn't react to any commands usually means a shorted CPU....have seen it happen a lot on TVs.

All good. My fault for being impatient. It's all a learning curve for me.It looks like the board or chip was fried anyway so I am not too stressed and have learned heaps which was the aim.
Thanks very much for all.your help. I will part the TV oit and move on.

[Dannyx]

Re: Lg 55lv5500 - ta

You could always get a new MB rather than scrap it

[Cibby600]

Re: Lg 55lv5500 - ta

You could always get a new MB rather than scrap it

LOL I have tried. They are not available anymore, and if they were, they want AUD$400+ !!!!!

Thanks again to all who chipped in with help and advice. It was a very enjoyable learning experience.
Think I'll keep my eye out for another dead TV in the future. lol

Cheers.

[tw2005]

Re: Lg 55lv5500 - ta

You could always get a new MB rather than scrap it

I was thinking of one from the US market and then a conversion fromthe dead board. I did find one but knowing they all fail, hard to trust what you're getting.

[jlbevo]

Re: Lg 55lv5500 - ta

Hi mate did you ever get anywhere with this? I have the same TV with the same issue and was thinking of buying a board for a 55LV5500-UA.AUSYLJR

Do you know if it would fit ok and would the only issue be you wouldn't be able to get Australian TV channels?

If I could get picture to display and the HDMI worked etc that would be perfect

[Michale32086]

Re: Lg 55lv5500 - ta

I realize this is a very old thread, but wanted to add my 2 cents...

I have an LG 55LV5500 and an LG 55LW5600... Both TVs use a Main Board with identical connectors, but a slightly different layout.. Both had the exact same symptoms . Power Light goes on, no sound, no backlight, no display...


Did a BADCAPS search on the 55LV5500 which led me to this thread... As TOM66 can tell you, I a a VERY big fan of reflows..

I have a AOYUE 968 Reflow Apparatus with a PH T-8280 IR PreHeat Plate..

I put the Main Board from the LV5500 on there after taking off the main chip heat sink.. Had a scare when I scoured over the traces with a screw driver.. Shallow scour.. No cut traces..

Whew!!! Dodged the stoopid bullet..

Put the board on the IR Plate Temp and heated to around 150C. Used the AOYUE and heated the main chip to 220c-230c for 1.5 mins...

SUCCESS!!!!

The LV5500 came right up!!

I put the board on the LW5600 and the TV also came up, but the display was really wanky looking. I am hoping that it's just because the boards are different model #s..

Doing the same process on the LW5600 and seeing if I can get lucky twice in one morning.. I mean, who wouldn't love that!!!!??

[Michale32086]

Re: Lg 55lv5500 - ta

Apparently, I wasn't destined to get lucky twice in one morning..

The LW5600 just wouldn't come up...

[حسين خطيب ابوعلي]

Re: Lg 55lv5500 - ta

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

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