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Shahid
Shahid, Technician
Category: TV
Satisfied Customers: 10109
Experience:  I have been repairing electronic gear since 1993 as a qualified Sony tech
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Think I alreadyvknow the answer to this one, but since ive

Customer Question

Think I alreadyvknow the answer to this one, but since ive never seen this exact symptom before, figured id ask. Ill send a pic once the question is picked up, but im thinkin this is a tcon issue. Exactly one half of the screen has thick colored bars, yellow and blue...menu pulls up, screen saver shows, but is distorted on the side with the colored bars.
Submitted: 2 months ago.
Category: TV
Expert:  Shahid replied 2 months ago.

Hi, my name is ***** ***** I will do my best to help you today. To make sure I don’t miss anything, please give me a minute to review your question.

Expert:  Shahid replied 2 months ago.

Yes, it could be t-con board issue, picture of TV is awaited please.

Customer: replied 2 months ago.

Im worried about that blue line that goes halfway up the screen in the right most bar...dont want to replace the tcon only to find out that the line is indicative of bad panel

Expert:  Shahid replied 2 months ago.

Ed, it is not t-con board issue as these are thick bars and coming from main board. Half line is definitely the display panel problem and will not go away with main board replacement.

Customer: replied 2 months ago.

Ok, gotcha. So main board replacement, then...or maybe I get lucky and its a connector or lvds cable. As far as the half line...do you think thats a problem that I can address by putting pressure on one of the ribbon cables connected to the display, as I have done in the past? I've never seen a HALF line, so I dont know if thats indicative of something different than I'm used to as far as display problems.

Expert:  Shahid replied 2 months ago.

Half line mostly appears due to leakage of liquid of crystal and not because of taping bond connection. I have never seen yet a half line got fixed by replacement of any circuit board.

Customer: replied 2 months ago.

K, ill find out. You have a fresh question to pick up, and two or three more coming so you can review them while i go out and run some errands

Expert:  Shahid replied 2 months ago.

OK, no problem.

Customer: replied 1 month ago.

Hey, so i took out tcon, and swapped the cables to see if it changed which side the bars were on....backlights light up....panel looks great, no problems whatsoever....no image or anything, but no bars or lines either. I think i damaged the tcon or main, though, cause now i cant get ANYTHING on the screen. I am going to look for a donor tv to try other parts from tonight

Expert:  Shahid replied 1 month ago.

I guess you were going to swap main board in this TV. It wasn't t-con board issue.

Customer: replied 1 month ago.

So now when i power it up...it turns on, and i get sound from a source....but no backlight and no picture...what can i test to make sure I didnt fry the inverter?

Customer: replied 1 month ago.

Sorry, but im basically going vack to square one now that i cant get picture or backlight, when i was getting backlight before i put it back together

Customer: replied 1 month ago.

Or....is there a reset procedure for this LG, like for others?

Expert:  Shahid replied 1 month ago.

I hope inverter board will be OK as it get volts from power board and main board controls the switching and intensity process.

Can you put old t-con board to get previous symptoms in TV?

Customer: replied 1 month ago.

I never swapped any boards

Customer: replied 1 month ago.

All same boards...i was just trying to swap the tcon cable feed from one side to the other to see if the lines went to the other side of the tv

Expert:  Shahid replied 1 month ago.

ah OK, swapping the output connectors of t-con board can damage the processor chip of t-con board or most likely the processor board inside display panel that drives the LCD pixels.

This kind of swapping/ switching should not be done. Do you have another t-con board or can check 12V on t-con board fuse?

Customer: replied 1 month ago.

I see. Wont be doing that again, then. Tcon fuse is ok, how do i check 12v on tcon?

Customer: replied 1 month ago.

Dont know if this info helps or not, but the blue light on inverter board comes on as the tv boots up, and then turns off when the sound kicks in. Tv runs for about 5 minutes, then shuts down into standby mode

Expert:  Shahid replied 1 month ago.

While TV stays On, you can check 12V on t-con board.

If 12V is missing that means main board trouble.

Customer: replied 1 month ago.

Ok, will do...is it at a test point, or one of the pins? If its one of the pins, which one (what number pin from the top or from the bottom, from the left or from the right? Some boards arent marked, unfortunately)

Customer: replied 1 month ago.

And i dont know if it helps, but power supply out to inverter board, all 5 24v leads measure 24.3v DC or so, error lead measures 0.0v DC, PWM-DIM measures 1.4v DC, INV ON/OFF measures 4.6v DC, BRI measures 1.6v DC. ALL measurements ON inverter board, same readings. I would also like to know how to put power to the ccfl backlights on this one, to test them. Seems to be just one pink wire coming out from inverter board to panel. Im guessing i just put my ccfl power supply positive lead on that wire.

Customer: replied 1 month ago.

Inverter is only putting out 1-2v AC (NO volts DC) when turned on, when when the blue light onthe back of the inverter board comes on. I measured the output on the ccfl tester, and it only measures between 1-2v AC (NO volts DC) on each side, even when connected to the one pink wire going out from inverter and in to the panel. The reading on display never gets over 88.0 (display reads Ammeter *10 mA), and im pretty sute it did before...like up to 200 or something. The CCFL tester came with a black and red lead, but on the tester itself it's not marked which is which, I cant see any of the ebay listings thay show probe orientation. Unless I'm using it wrong, and i need to combine the two leads or something, then my tester might be broken. If thats the case, can I produce the necessary voltage with my benchtop adjustable power supply?

Will show a picture of my ccfl tester, and a picture of my benchtop power supply

Expert:  Shahid replied 1 month ago.

Ed, is it possible to provide me picture of entire back of TV so I can view the boards and backlight wires?

There are several different boards associated to this one model and the picture will help to determine the boards.

Customer: replied 1 month ago.

Sure thing, gimme a few minutes to get back to that unit

Customer: replied 1 month ago.
Expert:  Shahid replied 1 month ago.

Ed, does the backlight turn On when power up the TV?

Customer: replied 1 month ago.

As of before i started f**kin with the t-con, yes backlight. Half a good picture, half a distorted one. As of right now, you hit power, and the LED indicstor light fades in and out red 3 times, then goes blue to power up, and it turns on but we now get no picture and no backlight

Expert:  Shahid replied 1 month ago.

Ed, can you tight the fixing screws on t-con board and check if it helps?

Customer: replied 1 month ago.

Yup, sure will. This one is a pain in the ass to get boards off of, lots of braces and brackets. I have another question already poated to you, and several more coming

Expert:  Shahid replied 1 month ago.

OK, please reply back with the result and I already replied your two more questions.