LG 42LK450 No sound, Horizontal lines

[Hopsing64]

Hi,

I have a LG 42LK450-UB with stationary horizontal lines across the screen. They are mostly green and purple with a large tan band across part of the screen. photo one. sorry forgot to rotate them. Also getting a whine/buzz on t-con board. I think its coming from the components marked 220 y2 in photo 2. The tv immediately goes to the lines. I get no menu or logo or any sort of source video. The back lights are on and if I remove one of the panel to T-con cables that side turns white. Voltages off the power supply are good, and the A-dim and p-dim are 3.1 with tv on. I'm thinking main board because of the no sound/no picture, but would like to verify that before buying a new one.

Thanks

[nomoresonys]

Re: LG 42LK450 No sound, Horizontal lines

that tcon sounds pretty iffy, I think I would replace that first, I can't recall hearing any noise from my tcons.

[selldoor]

Re: LG 42LK450 No sound, Horizontal lines

Checked the voltage at the fuse on the tcon (both sides) also test vgl and vgh.
I dont know what is "good" but someone will.

[Hopsing64]

Re: LG 42LK450 No sound, Horizontal lines

Voltage at fuse F1 on the t-con is 12 on both ends.
VGL 5.2
vgh 28.1
VIN 12
VCC 3.3

I also dug up a bad t-con and a working but with bad ldvs socket t-con for this tv. Both give me the same display and same buzzing from the two components on it.
Any other suggestions?

[nomoresonys]

Re: LG 42LK450 No sound, Horizontal lines

Voltage at fuse F1 on the t-con is 12 on both ends.
VGL 5.2
vgh 28.1
VIN 12
VCC 3.3

I also dug up a bad t-con and a working but with bad ldvs socket t-con for this tv. Both give me the same display and same buzzing from the two components on it.
Any other suggestions?

not sure, but makes me think maybe some signal going to the tcon is making it buzz?

[nomoresonys]

Re: LG 42LK450 No sound, Horizontal lines

would be nice if you had a spare mainboard to test with.

[budm]

Re: LG 42LK450 No sound, Horizontal lines

Buzzing sound from the inductors for the switching power supply on the T-CON usually indicates too much current being drawn by the LCD panel.

[Moreno83]

Re: LG 42LK450 No sound, Horizontal lines

Wich means that 1 or more backlight tubes are dead? Lcd is drawing to much power Budm?

[Hopsing64]

Re: LG 42LK450 No sound, Horizontal lines

The back lights work. They come on when the tv is powered on.