LG 47 LM8600 - No Video

[Davi.p]

on the topics list page,, after the group title, there's a big blue button " New topic"

[Longon]

I did not read all the posts, to pursue is better that you open a new thread and explain all your case, no good get another thread, and please if you can speak easilly, i find more trouble than the others to understand you.. before starting post do this, take an hot air gun or station and do a slight heating to the main processor, let's say 1 min. at 350C, do not follow who says to use an hair dryer, that is for comb the dolls, test the board when slightly warm , then report here what happened.. bye

Hi Davi......
Thanks for your reply...
As mentioned in your response I'll attempt your recommendation with my heat gun to see if helps.
I will also start a new thread which is what I thought I'd done but am still trying to get used to the workings of Badcaps!!
Catch up soon...and if you need me to explain a little clearer then please let me know.
regards
long

[Davi.p]

I did not read all the posts, to pursue is better that you open a new thread and explain all your case, no good get another thread, and please if you can speak easilly, i find more trouble than the others to understand you.. before starting post do this, take an hot air gun or station and do a slight heating to the main processor, let's say 1 min. at 350C, do not follow who says to use an hair dryer, that is for comb the dolls, test the board when slightly warm , then report here what happened.. bye

[Longon]

Re: LG 47 LM8600 - No Video
Hi all.....
I probably need putting against a wall and deserve a stoning for my stupidity.............. I have a LG which after following information with problems with T-con and lines on screen covered the pins which affected the display and had it sorted...until!!! Lets get it over and done with, I managed to get a little sidetracked and forgot that the tv remained powered up and I replaced the LVDS which to my horror then left me with no picture whatsoever. The backlight remains ok but as mentioned no picture and probably managed to fry the T-con or have I? Perhaps there may be something a little more simple or not so. Where do I go from here? Can you assist in any way? or as suspected into my pocket to find a replacement which is not where I want to go as not the most inexpensive board to say the least.
OK so now its out there let the stoning begin.....
Many thanks guys and stay safe(safer than me anyhow)
Look forward to your assistance
Regards
Long

[alfatv]

Re: LG 47 LM8600 - No Video

Can you get access to long boards attached to LCD? I think you need to remove metal cover(s).
Also disconnect cables from T-con one at the time and check if you see same behavior as before.

[anupkg1985]

Re: LG 47 LM8600 - No Video

Hi,

TV worked for couple of months and again there is no video. I checked lvds cable and looks good. Not sure what is the issue? Any pointers?

[anupkg1985]

Re: LG 47 LM8600 - No Video

Will try that. Looks good so far. Will update with findings.

[sigmeyer]

Re: LG 47 LM8600 - No Video

Could be a bad LVDS cable , you messing around with it probably reconnected some pins and now its working ... Maybe try messing with LVDS cable and see if problem happens again.

[anupkg1985]

Re: LG 47 LM8600 - No Video

After long time today I thought of resuming work on this TV and guess what, it started displaying video as soon I plugged the power cable. Now I'm not sure what was the issue and how long it will work. Can some one throw some light on this, what could have happened?

[Davi.p]

Re: LG 47 LM8600 - No Video

Mmmmmh... i' m not on this advice.. i think if bga work did not work the next purchase must be mainboard... but not before making some poking around on the panel's boards searching for obvouus short circuits on caps.

[Davi.p]

Re: LG 47 LM8600 - No Video

Right said Fred...

[anupkg1985]

Re: LG 47 LM8600 - No Video

To test the lvds lines in this design without external resistors you must test between the couples 12-13, 14-15 , 16-17, ....... 23-24, not from pins to ground..

Tested in pairs, some of them has 0.12V and some of them are just 0V. Not sure if that's correct. Will try luck by heating IC9300 or else will go for tcon replacement.

[Davi.p]

Re: LG 47 LM8600 - No Video

To test the lvds lines in this design without external resistors you must test between the couples 12-13, 14-15 , 16-17, ....... 23-24, not from pins to ground..

[anupkg1985]

Re: LG 47 LM8600 - No Video

On some models a problem to the panel,, can cause the tcon software to set a flag in the eprom that switches off the tcon in protection, but in this case , now i note, the tensions are present so no eprom problem. Now have to test if signals come to tcon, on the lvds rails at the eol resistrs 100 ohm, have to see a tension around 1,3v, if the rail that carries the sync signals is missing i think image is not displayed. This is somehow a rare defect i think. The option of mainboard cpu bad soldering is not impossibile, so a test on the lvds lines maybe can reveal cpu to tcon output.

I haven't done the test Diah suggested in above post with hot air gun however below are voltages I'm getting on the LVDS pins on mainboard -

PIN1 0.14V
PIN2 3.2V
PIN3 0.14V
PIN4-6 3.3V
PIN7-8 N/C
PIN9 3.2V
PIN10 N/C
PIN11-41 0V (most of them connected to IC9300 not sure if I can measure voltage on those?)
PIN42-46 GND 0V
PIN 47 N/C
PIN48-51 11.2V

[Diah]

Re: LG 47 LM8600 - No Video

Not sure but it's very confusing for newbie like me. I'm just concerned about the panel, if it's bad then there is no point to invest money in the t-con. Also I saw many videos of solving this issue by baking the main board in oven, do you think I should attempt that? I'm just concerned of damaging main board.

i do understand your worries and they are reasonable too because you dont know the history of the TV. also instate backing the MB. just use hot air gun to heat IC9300 after you recover all area around it to avoid SMT parts flying out by hot air.

[Davi.p]

Re: LG 47 LM8600 - No Video

On some models a problem to the panel,, can cause the tcon software to set a flag in the eprom that switches off the tcon in protection, but in this case , now i note, the tensions are present so no eprom problem. Now have to test if signals come to tcon, on the lvds rails at the eol resistrs 100 ohm, have to see a tension around 1,3v, if the rail that carries the sync signals is missing i think image is not displayed. This is somehow a rare defect i think. The option of mainboard cpu bad soldering is not impossibile, so a test on the lvds lines maybe can reveal cpu to tcon output.

[anupkg1985]

Re: LG 47 LM8600 - No Video

cutting off TX signal to panel always never being T-CON firmware issue. its MHz Freq cut off at the Main T-CON IC.. reasons always 1 of 3 this TX the main boards didn't send it because of BGA or the T-CON Main IC fault ( T-con replace ) and the third damage ( open circuit at the panel )

you did test one ribbon disconnected with video signal, and you got only white half mean reason No 3 out. stay 1 of 2 T-CON replace or MB BGA so easy some time the test will be.

Not sure but it's very confusing for newbie like me. I'm just concerned about the panel, if it's bad then there is no point to invest money in the t-con. Also I saw many videos of solving this issue by baking the main board in oven, do you think I should attempt that? I'm just concerned of damaging main board.

[Diah]

Re: LG 47 LM8600 - No Video

cutting off TX signal to panel always never being T-CON firmware issue. its MHz Freq cut off at the Main T-CON IC.. reasons always 1 of 3 this TX the main boards didn't send it because of BGA or the T-CON Main IC fault ( T-con replace ) and the third damage ( open circuit at the panel )

you did test one ribbon disconnected with video signal, and you got only white half mean reason No 3 out. stay 1 of 2 T-CON replace or MB BGA so easy some time the test will be.

[anupkg1985]

Re: LG 47 LM8600 - No Video

If you can get a CH341A programmer with clip you can easily reprogram the i2c eprom on the tcon, not the flash one near the input, or program it only if the i2c doesn't solve, but it's difficult to find the original dumps. Have you pressed button?

Yes, nothing happens by pressing that button on t-con.

[Davi.p]

Re: LG 47 LM8600 - No Video

If you can get a CH341A programmer with clip you can easily reprogram the i2c eprom on the tcon, not the flash one near the input, or program it only if the i2c doesn't solve, but it's difficult to find the original dumps. Have you pressed button?