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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 ?
Hi David, Recommend to check more on the power supply. check standby voltage https://www.youtube.com/watch?v=kmGVdUjW… check all voltages as well on the connector from power supply to the main board. (make a list and post on ifixit, it may enable people to help you) Measure voltages Both with motherboard connected and not connected. This hopefully can tell you if the fault is in the power supply. best of luck.
Hi @davemeran , Check what the voltages are on the power board and go on from there. Having no images on the screen whether there are backlights or not means the mainboard but if the power board isn’t supplying the correct voltages then it won’t work properly anyway. There are several versions of your model using 2 different chassis so here’s a link to the service manual for the different models and chassis that they have. I’ve checked both chassis models and they seem to have the same pinout/voltages for the power board.
(click on image to enlarge for better viewing) Hopefully a start
