42lg6100 horizontal lines going up and down screen

[Cscott0072003]

hi guys, when i turn my tv on i get the backlight come on everytime but it takes a few attempts at turning it on and off to get picture with some horizontal lines.. the lines disappear after 10-20mins at which point it will power on and off with picture everytime..i have visually checked for bad capacitors on power board and av board aswell as checked voltages at the t-con board fuse and all power board outputs..im sure its not a screen problem as the lines move up and down screen and are not stuck in one place like a bad tab on the lcd would show..

i think this is a common problem with the 42lg6100's as mine is identical to this problem on youtube..

http://www.youtube.com/watch?v=_IBXpivEZWk

[Cscott0072003]

Re: 42lg6100 horizontal lines going up and down screen

all of these orange bits on power supply have cracks in, not sure if this is normal.. i think they are fuses..




these are the results from voltage test on psu with what the power should be on left and what it tested at on right.. thanks for looking, any help appreciated

[vinceroger69]

Re: 42lg6100 horizontal lines going up and down screen

there ferrite beads i think i have seen those cracks before on them and still seem to do there job.have you got a esr meter to check the capacitors correctly also may be worth using a hair dryer to heat the boards up to see if you can make the fault time alter then you can narrow down the faulty parts heat the power supply first imo.

[Cscott0072003]

Re: 42lg6100 horizontal lines going up and down screen

thanks vinceroger69.. with the multimeter they all test as still connected.. replaced one cap on av board as it looked bad but didnt solve the lines.. its hard to tell if the smd caps are bad as most of the time they dont blow there tops off.. im not sure if the power supply voltages are correct..

[vinceroger69]

Re: 42lg6100 horizontal lines going up and down screen

try the hair dryer method about 3 to 4 mins on each board i guess do 1 board a time.

[Cscott0072003]

Re: 42lg6100 horizontal lines going up and down screen

I've tried similar with heatgun but at greater distance as its 320-520c..i was told to try freeze spray but havnt got any yet.. theres a button on the av board (internal switch only) and when the screen doesn't come on and its just the backlight on, i press the button on av board which i guess is an av board reset and that sometimes brings picture on..

[Cscott0072003]

Re: 42lg6100 horizontal lines going up and down screen

i missed the esr comment.. i dont have one, just a cheapy voltage meter.. i think it goes upto 600v but no good for capacitance.. all i can do with this meter is take caps out of board and test it with ohms setting i guess

[tom66]

Re: 42lg6100 horizontal lines going up and down screen

Post a pic of your main board?

[Cscott0072003]

Re: 42lg6100 horizontal lines going up and down screen

thanks tom, wasnt sure if you wanted main power board or main av board..if its powerboard i'll redo pics...

[Cscott0072003]

Re: 42lg6100 horizontal lines going up and down screen

pics of powerboard caps and power board if they help..

[Cscott0072003]

Re: 42lg6100 horizontal lines going up and down screen

i've done abit more checking about on the chips on the av board and found something that looks abit out of the norm... would this cause horizontal lines on all inputs?? thanks in advance.. also any ideas on replacing these coils will be amazing...

[tom66]

Re: 42lg6100 horizontal lines going up and down screen

I think that's just glue. I'd try checking voltage regulators.
https://www.badcaps.net/forum/showthread.php?t=22231

[Cscott0072003]

Re: 42lg6100 horizontal lines going up and down screen

thanks tom but i think something leaked as when i wiggled the coils it lost picture and comes back.. i think im just going to go with a new mainboard as i've wrecked this one by trying to take the tuner off..also the end pin in the bottom right of that circuit on the black strip is clearly there on the front but on the back its not on the mainboard.. time to hunt down a cheap ld89a board i guess...