Mobo replaced, tv turns on, backlight, sound ok, but no image. (UP)
Hello there, i would like to ask for your kind help.
I’ve got an LG 42LB5610 HDTV which was not working properly, did nothing on power on button.
Now that i’ve replaced the motherboard the tv turns on ( standby light flashes two times, then goes black, if i turn of the tv, it goes back red) but you can’t see screen, nor sound.
I’ve checked voltages between the backlight led+ and ground it gives 250V when the tv on button is pressed, then goes down to 108V slowly. Standby mode voltage is 65V. ( encirled the connector on the picture )
I’ would like to know if it worth checking the backlight led strips, or it can be a power supply issue ?
I’would be very grateful because ive got this tv as a kind of present because everybody nows im that guy who can repair everything, but im stuck with this one.
EDIT: I don’t know how to identify pin numbers, could someone help me with that?
EDIT 3 : I’ve measured power supply mb connector voltages, it seems to me that these are correct. @jayeff
i forgot to mention that on the opinion of my neighbour ive replaced mobo, but the label which came with the mb (bottom picture) states that it came from the LC420DUE (FG)(A6) screen, but on my tv (top pic) there is (A3) screen, could this be the issue?
mobo pic, serial numbers are the same
EDIT 3 : I’ve measured power supply mb connector voltages, it seems to me that these are correct. @jayeff
EDIT 4:
I have got two power boards, two motherboards, and replaced backlight leds.
I can turn on the tv, it has sound from hdmi input, backlight leds working but there are no image on the screen.
What do you think should i replace the t-con board ?
Es esta una buena pregunta?
4 comentarios
Found this on web:
"I bought a new power board, but it did same thing. I put old one back in and then figured out that what is happening is that when the TV comes out of standby, a signal is sent BACK to the power supply on the wire labeled "Fail" and the TV shuts down and flashes the power light. I disconnected that wire (just pulled it out of the connector, carefully by releasing the holding tab on the pin and pulling out the wire). I then plugged the connector back into the power board (with the fail wire disconnected) and the TV powers up normally. I have tested it for about an hour and don't see any issues...so I intend to run it like this and see what happens."
- de mike
Thanks Mike.
The thing is i already tried to find this fail wire unsuccessfully.
If you could help me with that, please.
- de David
@davemeran
Power board
- de mike
@mike
on my power board i can't find any wires labeled "fail"
- de David