Chosen Solution
Hello, I have a Toshiba 50L711U18, the backlight is not turning on. Tried using a flashlight and I can see an image. My phone also tries to connect to the chromecast on it as well. These two things are telling me that the T-con board and the main board are most likely working properly. I opened up the front of the display to get at the backlights. When testing them I noticed that a few of them are a dark blue, almost purple color. I read that they might be on their way out, could these few bad LEDs stop the rest of the backlight array from turning on? I left the TV unplugged overnight, when I plugged it in again the backlights did turn on for 10-15 seconds then shut off and flashed a 12 red light code. I also got a 5 flash code once but it hasn’t returned, the 12 is consistent. I plan on pulling the display off again and rechecking the LEDs, any other troubleshooting help would be much appreciated. I will post my voltages in an attachment.
Tyler Saboe “I read that they might be on their way out, could these few bad LEDs stop the rest of the backlight array from turning on”, absolutely! Since your backlight comes on for a few seconds and since you have a positive flashlight test, this sounds like failed backlight strips. Replace those strips since the LED’s have delaminated. Replacing the strips should fix this issue.
