Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.

[TheForgottenKing]

Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.

Update: The audio-out port also stops working when the rest of the audio stops. I fear it may be an issue with the main board.

[Diah]

Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.

from yours PSU photo, you have only 1 transformer between the HOT & COLD side, this mean to me that any issue at LEDs backlight strips will effected the currents at other rail such the main 13V. and in reverse wise if there issue at rail 13V will effected the LED BL, in this case we go first to check the cheap option which are the BL.

[TheForgottenKing]

Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.

from yours PSU photo, you have only 1 transformer between the HOT & COLD side, this mean to me that any issue at LEDs backlight strips will effected the currents at other rail such the main 13V. and in reverse wise if there issue at rail 13V will effected the LED BL, in this case we go first to check the cheap option which are the BL.

How should I check the backlight, and where do I get a replacement?

[Diah]

Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.

How should I check the backlight, and where do I get a replacement?

at yours case nothings better than eyes inspection to check the flickering LED in case one or more dont turn on. but consider the risk of yours screen size by disassembling.

[TheForgottenKing]

Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.

at yours case nothings better than eyes inspection to check the flickering LED in case one or more dont turn on. but consider the risk of yours screen size by disassembling.

I'll try to do this. The whole backlight flickers evenly so I'm not sure if it's one LED or something else.

It wasn't the power supply, I got another one and the issue persisted.

I'd rather avoid disassembling the panel, but is that the next best step besides replacing the t-con or main board? Also, is there any way to start the TV without the backlight connected? I tried disconnecting them but the TV refuses to start without them.

[alfatv]

Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.

1. You can take video, then go frame by frame, sometimes it's possible to see bad LED, it will turn off first.
2. Measure voltages at LED connector when backlight is on and off.

[Diah]

Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.

I'll try to do this. The whole backlight flickers evenly so I'm not sure if it's one LED or something else.

It wasn't the power supply, I got another one and the issue persisted.

try measure the voltage on BL sockets , you have 6 groups at least i can see from the photo, each group had one white wire i think its the LED-
so you need to measure with yours meter on mode 200V DC the black probe on chassis and the red probe on each LED+ wire (red/blue/grey) listed your reading over here.

[TheForgottenKing]

Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.

Welp, tried getting at the backlights and ended up breaking the panel.

No big loss though. Thread closed, I guess.

[Diah]

Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.

Welp, tried getting at the backlights and ended up breaking the panel.

No big loss though. Thread closed, I guess.

bad news..
you still can run the tv with out panel... to see our suspect was correct about the LEDs

[TheForgottenKing]

Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.

Already took it apart for disposal, but there wasn't any obvious damage to the LEDs. Also, the TV wouldn't start without the LEDs or LCD plugged in, so I guess we'll never know. I'm going to just sell the boards now.