Re: 42LG50 no backlight

Since there are no real local stores that carry electronics supply/parts anymore and I don't really want to wait a week or more to order something with the chance it won't work (and not have a TV in the interim), I ran out to Radio Shack to see what I could find. Picked up an in-line fuse holder and a standard fast-blow glass fuse rated 3/4 amp. Since the fuse holder wires were a bit beefy for the surface mount soldering, I also purchased some 22 awg wire to transition from the lands to the fuse holder. Put it all in place and did a quick test before taping...

Re: 42LG50 no backlight

Thank you. You guys have been very helpful.
The bad news is that I can't seem to source this board (1420H1-20D-Master) on ebay (or anywhere else through a simple google search). I'm only seeing the slave inverter board, not the master. I suppose I can try to source the fuse itself and perhaps get lucky that nothing else is shot.
DPAL - do you recall where you found that same fuse?

Re: 42LG50 no backlight

So, the 4 white ones measure between .3 to 2 ohms, so they are good. That one black one, when I put the leads across it, starts around 15 M ohms and slowly goes down until it settles around 9 M ohms. Is this what you were saying would happen if it's bad?

Re: 42LG50 no backlight

Thanks for the info. I somehow missed that the black fuse was the OP's issue.

I can simply put the leads of an ohmmeter on each side of the fuse while there is no power to test if the fuse is open or not, correct? I've been a bit hesitant to work near the inverter boards with the TV energized.

Re: 42LG50 no backlight

I'm having the same issue as Torpex505. Plug the TV in, I get the red standby light. I press the power button and the blue light comes on, but no backlight on the screen. The flashlight test does show the menu on the screen, so it seems like just a backlight issue. Caps all look visibly ok. I also checked to make sure the 4 white fuses on the master invertor aren't open, but just noticed dpal's mention of the black fuse, which I'll test in the morning (near my bedtime here).
Torpex, did you ever find a resolution?