LG LCD TV 42HL30 too dark

[derekjankowski]

My LG 42HL30 is showing up too dark.
After hours of resetting set to factory defaults and checking the options and adjusting the levels, it does not improve.
The blacks are a bit blurry around the edges most of the time, and once in a blue moon the brightness pops back for 1-2 seconds them goes dark again.

The screen looks like a negative image.

I opened it up and checked for obvious blown caps, nothing obvious was found. I didn't test them with any kind of metering or diagnostic equipment.

The sound is good and I get the same results (through 2 separate HDMI cables) from my BLU RAY player.

From time to time when I first power on the TV it appears brighter (normal) and then it goes dark as described above and stays that way.

Here's how it looks

http://youtu.be/crCHwwy1LvE

Not sure if my iPad captures the issue.

[selldoor]

Re: LG LCD TV 42HL30 too dark

Perhaps try to find a pin on the main board named Dim and monitor the voltage on it when it is on bright and then goes dark.

[budm]

Re: LG LCD TV 42HL30 too dark

I would check the Gamma voltages on the T-CON board, it does not look like the backlights changing brightness problem.

[derekjankowski]

Re: LG LCD TV 42HL30 too dark

Thanks for the advice. It does seem like the brightness is kinda all over the place depending on the image on the screen. It does indeed brighten during sports or brightly lit multi camera programs (late night talk shows) and then the darks get too dark. Its almost like something isn't compensating for the shifts in brightness... off to check into it.

[martino]

Re: LG LCD TV 42HL30 too dark

No T-con board on this one,two ribbon cables from main straight to panel....

[derekjankowski]

Re: LG LCD TV 42HL30 too dark

Just an update... haven't had time to pull this TV apart and follow the advice noted here, but when the wife switched on the TV last night, the brightness came back and then some!

Now its too bright! Its stayed that way all night (well for a few hours). Crazy stuff.

[derekjankowski]

Re: LG LCD TV 42HL30 too dark

Another update. Got my hands on a good priced main board and power supply. The brightness subsided and went darker and the colours went off again. As seen in the first YouTube video.

I put both parts in, one at a time, and the problem persists. By process of elimination, its either the T-CON board, a bad cable connection somewhere (which has also been checked now and all seems firmly in place) or a bad panel.

I took the long way around but I think I'm narrowing down the search to solve the problem.

[tom66]

Re: LG LCD TV 42HL30 too dark

As requested above please check the T-CON gamma voltages. If you need help with this, post a picture of your T-con

[derekjankowski]

Re: LG LCD TV 42HL30 too dark

Actually I found a local Kijiji ad wanting 20 bucks for a TCON. I put it in and bingo! It fixed the issue!! Now I'm gonna take a voltage meter to the old one where you all specified and confirm your first suspicions!

Thanks for all the help!