Toshiba 50L2300U flickering horizontal lines, black (dimmed) screen

[SdlewisSr]

About 4 months ago I went to a friend's house to look at their TV. It was a Toshiba LED model 50L2300U. It had flickering horizontal lines in the bottom quarter of the screen (see attached photos). At the time she did not want to pay to have it repaired so she continued to use it until this week when the screen went black. She purchased another TV and gave me the Toshiba for parts or to fix it if I could.
When I got the TV home, the screen worked (with horizontal lines as mentioned above) for a few seconds to a few minutes after turning on the TV. After removing the back cover and checking the voltages, I discovered that the main board was just dimming the screen. The voltage on the PWM pin was only 1v. I jumpered the BL ON/OFF to the PWM so that I could keep the screen on to take pictures and allow the channels to program. She only used a cable box via HDMI. I found the lines are present when using the tuner in addition to HDMI. Here is a link to a short video of the lines (https://youtu.be/kW7xyUYVffk). I am assuming that whatever is causing the horizontal lines is causing the main board to dim the screen.
After searching online, I found many others having problems with these lines on Toshiba LED TV's, but no solutions. Has anyone experienced this before and resolved it?

[ReeceyBurger123]

Re: Toshiba 50L2300U flickering horizontal lines, black (dimmed) screen

Failing panel not fixable sorry

[SdlewisSr]

Re: Toshiba 50L2300U flickering horizontal lines, black (dimmed) screen

Big Bummer
This TV has a Sep 2013 manufacturer date. When I was checking the Toshiba forums, I found this same problem and they were only a couple years old also.
Thanks for your help

[SdlewisSr]

Re: Toshiba 50L2300U flickering horizontal lines, black (dimmed) screen

ReeceyBurger123 the lines are not random. They cycle on for about 2 seconds and cycle off for the same amount of time. See video (https://youtu.be/G7WzX4tTLA0). Is there any chance that this is being caused by the T-Conn or by something other than the panel?

[ReeceyBurger123]

Re: Toshiba 50L2300U flickering horizontal lines, black (dimmed) screen

Its the panel nothing else, the driver is shorting and causing distortions. I actually sold a 50" Toshiba 6 months ago with Lg panel failed in the same way with horizontal lines just this week.

[SdlewisSr]

Re: Toshiba 50L2300U flickering horizontal lines, black (dimmed) screen

OK. Thanks for your assistance. Have a blessed day

[SdlewisSr]

Re: Toshiba 50L2300U flickering horizontal lines, black (dimmed) screen

Just a final note. I decided to check the backlight LED's. I replaced 10 bad LED's and the backlights now work normally. Still have the horizontal lines.

[budwich]

Re: Toshiba 50L2300U flickering horizontal lines, black (dimmed) screen

not sure of the panel design, but in sharp / visio / sony, if there are tabs on the sides of the panel (each side), then you might be able to "save" the panel by removing the side that is bad. On mentioned panels, this "operation" allows the set to still function and look normal.

[SdlewisSr]

Re: Toshiba 50L2300U flickering horizontal lines, black (dimmed) screen

Hi budwich,
this has tabs only on the bottom.

[budwich]

Re: Toshiba 50L2300U flickering horizontal lines, black (dimmed) screen

:-( OK.... but there is also the "tape cutoff / mask" method. On sets where the bottom tabs are also responsible for driving the sides, people have found the placing a small piece of tape to mask off a bit of the pins on the connector (of interest) at the tcon to panel connector provides a similar "save". You might try that... you have to experiment a bit to find the right position and pins to mask. There are various threads about this and the success. The method isn't as "drastic" as the "side tab removal" so there is nothing lost in the experiment. It would be a shame that you spent the time to replaced leds and can't get a good display out of the panel.

[SdlewisSr]

Re: Toshiba 50L2300U flickering horizontal lines, black (dimmed) screen

Thanks budwich!
I will look into this method.

[budwich]

Re: Toshiba 50L2300U flickering horizontal lines, black (dimmed) screen

just one more point... I don't think you can see "side tabs" from the back of the set. You need to remove the bezel and look at the front side..... just in case you are making the statement about "no side tabs" based on your posted pictures or you know for a fact.

[SdlewisSr]

Re: Toshiba 50L2300U flickering horizontal lines, black (dimmed) screen

I had the panel apart repairing the LED's and know that the tabs are on the bottom only. I will look into the "tape cutoff / mask" method.

[SdlewisSr]

Re: Toshiba 50L2300U flickering horizontal lines, black (dimmed) screen

I finally got around to trying the taping/masking off method. I watched this "Do It With Dave" YouTube video (https://www.youtube.com/watch?v=j7vl7-vZEL8) which pointed me in the right direction. I masked off a portion of the right edge of the left ribbon cable leaving the T-Con board (see attached photos). It was trial and error finding the exact size of tape to use and where to use it. In photo (IMG_4334.JPG) you can see a black dot on the cable which marks the inner edge of the piece of tape that I used. In photo (IMG_4339.JPG) you can see the tape shining where it covers the connections. You can see the working TV picture at (https://youtu.be/FAHFmqIeDTg).
Thanks to everyone who posted with helpful suggestions!!!!
Have a blessed day!!!!

[budwich]

Re: Toshiba 50L2300U flickering horizontal lines, black (dimmed) screen

glad it worked out