LG 47LV5500 - No picture, no back light, no sound, powers on.

[vinceroger69]

Re: LG 47LV5500 - No picture, no back light, no sound, powers on.

I just repaired one of these L.G. 47LV5400-UB, set would turn on/off, it had no back llight, sound or video (voltage for led+ was 36 volts) Scoping the lvds cables to the t-con had no signal at all. I fluxed & re-heated the main bga chip under the large black heatsink (main board), and the set has been working fine. (backlight voltages +54 when lit).

Did you use a bga station or just hot air station? ive had good results with using proper flux and pre heating the bottom of the board then moving too the top with just a normal hot air staion ive done this on laptops/x box and two tv boards and none have came back too me.

[bajangerry]

Re: LG 47LV5500 - No picture, no back light, no sound, powers on.

Hi Guys, I have the same problem with my 47LV5500. I would like to get some guide as to where to check voltage levels as unfortunately I don't have any hot air tools to heat all the joints at once. Does anyone have a service manul type doc they can share with me?

[bajangerry]

Re: LG 47LV5500 - No picture, no back light, no sound, powers on.

FYI, found a training guide if anyone else is interested:
https://cdn.badcaps-static.com/pdfs/...607b18b88d.pdf

[lar7mirassou]

Re: LG 47LV5500 - No picture, no back light, no sound, powers on.

The heat solution actually works!! Thanks a thousand!! I reflowed the main board's main IC (the one underneath the heat sink) with a heat gun and flux paste, and it solved the issue beautifully!

[fliph]

Re: LG 47LV5500 - No picture, no back light, no sound, powers on.

Can we continue this?
494-496 across caps, 3.4 at PWR-ON, 24 at 24, 11.8 at DRV-ON

[budm]

Re: LG 47LV5500 - No picture, no back light, no sound, powers on.

Can we continue this?
494-496 across caps, 3.4 at PWR-ON, 24 at 24, 11.8 at DRV-ON

494 ~ 496 what across what caps?
11.8 at DRV-ON, you need to recheck your reading since no way you can have 11.8V at DRV-ON pin. May be you count the pin wrong?
How about all other Voltages at the other pins?
And how about showing us the pictures of YOUR boards and what is the problem you are having?

[fliph]

Re: LG 47LV5500 - No picture, no back light, no sound, powers on.

Sorry I am brand new to forums. I have a LG 47LW5700-UE that I am trying to repair and I found this thread in doing research.

No picture, sound, or backlight, led is lit when plugged in.

Led fades off/on when power button pushed.

Main filter caps C612~c614 read 495vdc.

P201

error 0
pwm 11.83
n. c 11.83
drv-on 11.83
vsync 0
gnd 0
3.5 3.52
3.5 3.52
gnd 0
gnd 0
24v 24.3
24v 3.42

I do not have pic capabilities right now (working on it)

Can any one help?
Please

[budm]

Re: LG 47LV5500 - No picture, no back light, no sound, powers on.

Please make a new thread since your TV is not the same model as the OP, it will make it easier for other people that are trying to repair the same model as yours in the future when they search the threads.
BTW, 'Main filter caps C612~c614 read 495vdc.' that must be measurement error, most of the TV's with PFC boosted Voltage use 450V DC rating cap, so if you really have that much Voltage I would think those caps will blow up. What did you use for meter ground when you make that measurement?

[cspiddler]

Re: LG 47LV5500 - No picture, no back light, no sound, powers on.

Want to thank everyone for their great advice and guidance. Had the same problem with a throwaway I picked up. Went through all the steps to confirm the power board and backlights were good so looked like time to follow your advice and give the main board a shot. Pulled the main board an removed the heat sink. Most of the hot air work I do is on individual small parts so normally use a quite small nozzle. Change to a larger nozzle that seemed appropriate for the larger video chip, set to 400 degrees, applied flux and heated slowly getting the nozzle closer over time. Applied light down pressure and watched the coloring of the flux, video chip and surrounding area. Took about 5 minutes or a bit more to bring chip up to temp slowly. After cool down, cleaned the board, replaced the heat sink, reinstalled the board and darn if it didn’t work like new. So reflowing the video chip really woks. How long? Well it’s been a week running daily. Maybe it will last till something else fails which could be years. Anyway , thanks again. This forum helps lots of us who rarely post but read and follow the advice given.