LG 47SL80 Horizontal "Dashes"......

[Michale32086]

Horizontal Dashes in an LG LCD TV

Main board or Tcon???

[Andrew F. Ali]

Re: LG 47SL80 Horizontal "Dashes"......

Try cleaning and reseating the LVDS cable at both ends and the FFC on the T-CON Bd. to the Source/Panel Bds. Looking again at your 2nd pic, is the image showing whitish on the screen?

[Michale32086]

Re: LG 47SL80 Horizontal "Dashes"......

Nope.. That's just the glare...

This appears to be an LCD and has a pair of ... crap brain fart... can't remember their name... Diverter boards??.... INVERTER!!!

It has inverter boards.. Maybe they are the problem???

[Andrew F. Ali]

Re: LG 47SL80 Horizontal "Dashes"......

Are they flashing or are they stationary? Actually I've never encountered anything like this before.

[Michale32086]

Re: LG 47SL80 Horizontal "Dashes"......

They seem to be moving all over the screen...

I'll get a better pic when I get to the shop...

[dick_barton]

Re: LG 47SL80 Horizontal "Dashes"......

Have you tried just running the test pattern as shown in the attachment. It would eliminate the panel and Tcon as the fault.

[Michale32086]

Re: LG 47SL80 Horizontal "Dashes"......

Thanx for that.. I'll give it a shot..

Everything looks clear except jumpering the 12v from the fuse to the SMPS board??

What's the SMPS Board??

[Andrew F. Ali]

Re: LG 47SL80 Horizontal "Dashes"......

SMPS: Switched Mode Power Supply.
So that would be your PSU or Power Bd.

[Michale32086]

Re: LG 47SL80 Horizontal "Dashes"......

OK Thanx.. I mis-read it..

Gimme a few to set this up..

[dick_barton]

Re: LG 47SL80 Horizontal "Dashes"......

If you have an external power supply you can use that to power the Tcon

[budwich]

Re: LG 47SL80 Horizontal "Dashes"......

close check the LVDS cable between the main board and tcon... both in terms of the cable itself (ie. any bends, etc) and the connectors / pins. Those look like "transmission errors".

[Michale32086]

Re: LG 47SL80 Horizontal "Dashes"......

OK My TCON is a bit different than the one in the picture..

I have found corresponding connections for the LVDS connection, but I can't find any 3.3v VCC...

I have found a VIN, a VDO and a VA1....

[R_J]

Re: LG 47SL80 Horizontal "Dashes"......

That sure looks like high voltage arcing causing the lines, does this tv use an inverter and ccfl lamps? If it does I would check the high voltage inverter connections (or capacitors) or it could be a cracked ccfl.
You should be able to here it, like a sizziling sound.
Post a picture of the rear of the tv and if it does have inverters there are likely two, master and slave post pictures of them also
They could look like these

[Michale32086]

Re: LG 47SL80 Horizontal "Dashes"......

Yea, it does use the CCFL lamps. It's got an inverter on either side..

In answer to a previous question.. Some of the horizontal lines are stationary and some are flashing up and down..

[Michale32086]

Re: LG 47SL80 Horizontal "Dashes"......

That sure looks like high voltage arcing causing the lines, does this tv use an inverter and ccfl lamps? If it does I would check the high voltage inverter connections (or capacitors) or it could be a cracked ccfl.
You should be able to here it, like a sizziling sound.
Post a picture of the rear of the tv and if it does have inverters there are likely two, master and slave post pictures of them also
They could look like these

Yep, that's exactly what they have...

I don't hear any sizzling or arc'ing when the TV is on..

[diif]

Re: LG 47SL80 Horizontal "Dashes"......

Looks like it could be a BGA issue, any change to the lines of you heat the main IC on the mainboard ?

[R_J]

Re: LG 47SL80 Horizontal "Dashes"......

You can try disconnecting the power going to the inverter,(try one then the other) the backlight will not stay on but you may be able to use a flashlight to see if the lines are still in the image

[Michale32086]

Re: LG 47SL80 Horizontal "Dashes"......

You can try disconnecting the power going to the inverter,(try one then the other) the backlight will not stay on but you may be able to use a flashlight to see if the lines are still in the image

Good idea..

Lines are still present with the inverters unplugged...

[Michale32086]

Re: LG 47SL80 Horizontal "Dashes"......

Looks like it could be a BGA issue, any change to the lines of you heat the main IC on the mainboard ?

I did do a rudementary reflow, not concentrating on the BGA, which I assume is the chip outlined in the pic??

[R_J]

Re: LG 47SL80 Horizontal "Dashes"......

Good idea..

Lines are still present with the inverters unplugged...

well that eliminates that idea. By chance do you have a scope? I might suspect a noisy ldo/bad cap like the ones near the power supply plug above ic1 in the picture