LG 55LV5500-UA.AUSYLJR - Does not turn on, no sound, no picture

[ngth82]

Re: LG 55LV5500-UA.AUSYLJR - Does not turn on, no sound, no picture

I received the new main board form LG today. Part number is EBT62012702 for this tv. I swapped out the board and it fired up just fine! thank you for all those who helped and commented. Total investment: ~$180

Onwards to the three additional project TV's that I have in the garage!

[budm]

Re: LG 55LV5500-UA.AUSYLJR - Does not turn on, no sound, no picture

Thanks for the follow-up on the repair.

[dick_barton]

Re: LG 55LV5500-UA.AUSYLJR - Does not turn on, no sound, no picture

Glad to hear that you have your set up and running again.

[Jim Nemmers]

Re: LG 55LV5500-UA.AUSYLJR - Does not turn on, no sound, no picture

mark

[fjutrackx]

Re: LG 55LV5500-UA.AUSYLJR - Does not turn on, no sound, no picture

Hi,

I had exactly the same problem with a tv (LG 37LV375S-ZC - LD12B)
I measured the same things, same results. But as a last test, i heated up IC101 with a hot-air solder-gun while starting, without the heatsink, and the tv booted up again. Probably it's the same problem as yours.

[ngth82]

Re: LG 55LV5500-UA.AUSYLJR - Does not turn on, no sound, no picture

Hi,

I had exactly the same problem with a tv (LG 37LV375S-ZC - LD12B)
I measured the same things, same results. But as a last test, i heated up IC101 with a hot-air solder-gun while starting, without the heatsink, and the tv booted up again. Probably it's the same problem as yours.

Good to hear. Please post any updates on your TV (longevity, failure rates, etc). That information may be worthwhile for other folks who is experiencing the same set of issues with this particular model TV.

Thanks!

[keysal]

Re: LG 55LV5500-UA.AUSYLJR - Does not turn on, no sound, no picture

My LG 55LW5600 UA. AUSYLJR problem is exactly like yours.
Back lights can be jumpered to forced on fine.
TCON fuse is fine.
The front panel touch sensitive power buttons works fine and turns on the power and turns from red to white but no backlight and no booting.
I figured the IC601 or IC602 eeproms were hosed. But I also noticed the IC reset tactile momentary switch above the service port and figured I would reset them and see what happened and the back lights would come on as long as the reset button was pushed.

I searched around and found the two IC's listed on the encompass web site.
The IC601 was available but not the IC602. Im wondering if I should attempt an IC swap and does anyone know who might be able to program an IC like the IC602.

Also noticed a guy on youtube that has a four part video repairing this main board.
https://youtu.be/4rsKjlWPmKk

I still havent found the software he mentions in the third or forth video that lets you connect to the service port and check for errors.
Has anyone tried this yet?
Thanks

Hi Guys... here's an update:

I looked at the 55LV5600 service manual and saw there is a Turn On Command Circuit drawing (attached). Since the power board of my 55LV5500 is common to the 55LV5600, i traced the turn on sequencing.. This is what i found:

• Step 1 is good: I have +3.5V_ST at the IC602 (MICOM) and Q502.
• Step 2 is good: Key 1 and Key 2 are both high (3.3V)
• Step 3 is good: RL_ON is asserted by the MICOM and can be traced all the way to the SMPS board.
• Step 4 is good: +12V and +24V are up on the Main Board.
• Step 5 is good: The +12 and +24V monitors are wired-OR'ed together. The output is high. POWER_DET is good.
• Step 6 is good: The switching regulator for +3.3V_NORMAL is good as well.
• Step 7 is good: PANEL_VCC (+12V) is seen on both sides of the T-CON board fuse.
• Step 8 fails. INV_CTL out of IC602 (MICOM) is HIGH. This drives the Q504 base HIGH, and the collector node LOW to INV_ON. INV_ON is DRV_ON on the SMPS board. The TV backlights are still off and no further turn on sequencing is observed.

Other observations:
The service manual states if either P202 or P203 (the connectors for the panel backlights) are disconnected, the backlights should turn on for about 4 seconds then turn off. This doesn't happen. (But i think it's a red herring for me since the DRV_ON signal is not working in the first place!)


I believe the MICOM (IC602) input conditions should be satisfied. So it sounds like i have a busted main board and unfortunately it's the microcontroller with proprietary firmware.

Does anyone have any additional ideas? or if this board is still available for sale? I checked shopjimmy and eBay, but couldn't find an exact match for the LG 55LV5500-UA.AUSYLJR TV model number, or the EAX63333405(0) main board.

Thank you,
Thomas

[Shush]

Re: LG 55LV5500-UA.AUSYLJR - Does not turn on, no sound, no picture

Hello All!

I want to share my story with you:

I have the LG 37LV550y which is the israeli version of the LV5500, and yesturday, after 6 years of great service, my tv suddenly went black and no sound came out of the TV.

My TV's symptoms was the same as in this post:
1. when i apply AC, the power LED turns red then white then turns off.
2. when i press the power button, the power LED goes red, then white and stays white.
3. the backlight is not turning ON.
4. no picture on screen (even with a flashlight)
5. no audio
6. after i turn on the TV, it does not responde to any key pressing on the remote, except the power button.

I used this post to disasmble the TV and i have checked all the DC voltages in the DC board - everything was ok and according to the training document.

Also, i have used the tests mentioned in the training document to force the the backlight ON and it was working fine.

Because i did not have any problems with lines and sync in my TV i have concluded that the problem is not in the TCON board.

Eventually i have decuded that the problem was in the main board.
I realized that there was nothing i could do to debug the problem because it will require advanced instruments (scope and ETC) and huge amount of time.

for me, no store wanted to take my TV for a repair, and I have been told that ordering a new main board would take 60 days(absurde amount of time without a TV) and that it will cost like a new TV.

I didn't have a choice, so i have decided as a last resort to put my main board inside my kitchen OVEN!
So i stripped the main board from the heatsinc, from all the metal and decals on the board, and i have put the main board inside a pre-hitted oven for 8 minutes in 200C.

I have covered my oven's plate with a foil, and i have made 4 foil balls and i have put the balls beneath the corners of my board so the board will be sitting on those balls aligned to the plate with the main CPU on top, and so nothing will touch the parts that are on the PS side of the board.

After 8 minutes i took the board with the plate outside the oven and let it cool.

Afterwards i have assembeled everything together and IT WORKED!
The TV turns on perfectly like the problem was never there.
I am still totally shocked!

Hope this would help someone in the future.

[Nick's Tvs]

Re: LG 55LV5500-UA.AUSYLJR - Does not turn on, no sound, no picture

What you have done is performed a re-flow, this is only a temporary fix. The main CPU chip is not properly attached to the main board and will need to be serviced in order to make sure that it is. I highly recommend for people not to try this at home unless it is their very last resort. There are repair services out there that will be able to perform a repair on the board which will include either a reball of your chip or replacement of the chip with a new one if necessary.

[andysantosa]

Re: LG 55LV5500-UA.AUSYLJR - Does not turn on, no sound, no picture

Hi,

I had exactly the same problem with a tv (LG 37LV375S-ZC - LD12B)
I measured the same things, same results. But as a last test, i heated up IC101 with a hot-air solder-gun while starting, without the heatsink, and the tv booted up again. Probably it's the same problem as yours.

My TV, LG 3D 55LW5700 also had the same problem, no video, no backlight, red indicator was flashing (slowly)

Check the power supply:

1. Unplug P502 connector in the Main Board
2. Jumper SBY3.5V to PWR_ON, relay is clicked, there is 12 & 24 volt in P201. C256&C257 53 volt
3. Jumper SBY3.5V to DRV_ON, backlight is on, C256&C257 63 volt
4. Plug P502 connector back, turn on the tv, DRV_ON is not 3.5v (measured around 40mv), so the issue appears to be with the main board.

Based on your info, I heated up IC 101 using hot air gun set to 370°C for 2 minutes (without heatsink) and it worked! , save me $150 (LG technician has checked my TV, he said the problem was in the power supply board, and it costs $150)

Thank you all for sharing this information.

[gtremblay]

Re: LG 55LV5500-UA.AUSYLJR - Does not turn on, no sound, no picture

Hi, I know I'm late for this post
I read this post since have got a 42LV5400 tv which have the exact sames symptoms...


a try few things:
-testings the power supply :
SMPS TEST 1: Force Power Supply On.
SMPS TEST 2: Force the Backlights On.
I do the tests with the power supply and everything seems "fine" except no drv-on voltage and only 36 volt on LED.
But with the test 2 , the led light on and stay on. (44 volt when on on pin 1 and 13 on connector)
And if a disconnect p202 or p203, Light come up few seconds then shut down as it should.



So I try to bake the mainboard few times, but does'nt help... the first time, led come up but the tv still does'nt boot... and then , just nothing except power up and power led stay white...



So I buy a new board which supposely tested and working...
But... Still same result...


When power up.
Red light appear which fading to white and fade out after
then white light appear again and stay white...

no sound, no picture, no backlight...

I doubt that 2 mainboard have the exact sames symptom result....

Should I try to bake the second mainboard I buy which was tested and working before shipped?

Do the answer to this problems is always the mainboard?

[tvtimmy]

Re: LG 55LV5500-UA.AUSYLJR - Does not turn on, no sound, no picture

NO! Try and return it and try another one. These mainboards are well known for bad bga solder. It might take a few of them to find a working one.

[gtremblay]

Re: LG 55LV5500-UA.AUSYLJR - Does not turn on, no sound, no picture

okay, thank you for the quick answer.
Since shipping cost is more than the motherboard itself, I'll keep it and do more tests... nothing to loose at this point

Thank you for the advice, I'll check for another board at the same time.

If I have any success, I let you know!

[gtremblay]

Re: LG 55LV5500-UA.AUSYLJR - Does not turn on, no sound, no picture

After doing all the tests with the power supply (via the service manual).
I decide to put the new board received (used) in the oven at 385 for 10 min.

guest what...
I WORKED!!! hahah

with the last board (original one), I try the same things about 5-6 times wihout success...

but this times with the new board, one times and the TV start again!

model 42LV5400
power supply eay62169801
service manual for the power supply board

https://cdn.badcaps-static.com/pdfs/...607b18b88d.pdf

the link is for the manual of the 55LW5600 models but it's the same power supply board. (Sames tests).

with the PSU tests, everything was ok except DRV-on at 0 volt and leds at 36 volt instead of 54v (without drive on)
with drv-on (via test B of the power supply) it was 44 volts on pin 1-12 and 1-13 of the led "drive"


Thanks you!!!!

[gtremblay]

Re: LG 55LV5500-UA.AUSYLJR - Does not turn on, no sound, no picture

well... don't know if related but I notice other problems.. so I start a new thread
https://www.badcaps.net/forum/showthread.php?t=78588