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.
TheForgottenKing
Member
Last Activity: 11-27-2022, 08:07 PM
Joined: 04-18-2021
Location: Chicago
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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.Leave a comment:
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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.
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....Last edited by TheForgottenKing; 04-23-2021, 10:22 AM.Leave a comment:
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Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.
How should I check the backlight, and where do I get a replacement?...Leave a comment:
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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.Leave a comment:
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Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.
1920x1080, I'll try a usb movie once I reassemble the TV....Leave a comment:
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Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.
The sound issue occurred over both HDMI and 3.5mm, I've been using this with a PC and laptop. I've got a new power board and will test that, I suspect it might be an issue with something that powers the 13V rail which seems to power the speakers....Leave a comment:
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Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.
Where should I look, and what's the process for checking the LEDs? And why would this cut off the sound at the same time?...Last edited by TheForgottenKing; 04-19-2021, 03:10 PM.Leave a comment:
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Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.
LED pinout:
Pinout to the board:
At this point I've bought a cheap replacement power supply just to test if this one is the problem. I'm hoping it's not the main board.
For anyone interested, I'm using [URL="https://elektrotanya.com/sharp_lc-60-70le650u_70le657u_70757u_c6500u_le755u_le857u_c7500u.pdf/download.html"]this manual[/URL].Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.
LED pinout:...Leave a comment:
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Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.
I've attached images of the power supply, main board, and tcon board respectively. Please do specify if you want a closeup, but I don't see anything immediately obvious.
...Leave a comment:
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Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.
Unfortunately I was wrong about my statement of the speakers being attached to the power board, they are attached to the main board. I've attached an image of the block diagram.
...Leave a comment:
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Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.
Will do this as well. W̶o̶u̶l̶d̶ i̶t̶ b̶e̶ w̶o̶r̶t̶h̶ t̶r̶y̶i̶n̶g̶ t̶o̶ h̶e̶a̶t̶ t̶h̶e̶ b̶o̶a̶r̶d̶ i̶n̶ a̶n̶ o̶v̶e̶n̶ t̶o̶ r̶e̶f̶l̶o̶w̶ t̶h̶e̶ j̶o̶i̶n̶t̶s̶?̶
Will not do this. Pretend I never said that. Is there a particular reason this is a bad idea?...Last edited by TheForgottenKing; 04-18-2021, 08:55 PM.Leave a comment:
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Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.
Will do this as well. Would it be worth trying to heat the board in an oven to reflow the joints?...Leave a comment:
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Re: Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.
I'll disassemble it tomorrow before work, and try to get some up-close pictures. Is there any areas of interest?
I haven't taken any voltage measurements. I'll try to do so but the intermittent style of the problem might make this difficult.
The remote control continues to work, and the TV continues to properly display an image. The backlight and image stays on, it's just a quick flicker and the image continues to work after....Leave a comment:
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Sharp LC70LE755U - Intermittent backlight flickering and loss of sound.
Hello everyone, first time posting here so I hope I'm doing everything right.
I just came into possession of a Sharp Aquos LC70LE755U. It was free for me, so with the stand and power cable I only have $30 in this. As such, I'm trying to repair it for cheap.
It works most of the time perfectly, except for an issue with what I think is the power supply. After anywhere from 10-30 minutes of usage, the screen backlight will flicker briefly, and the sound will completely stop working. The sound doesn't start working until I unplug the TV, wait a few seconds, and plug it... -
Re: New Members - please post your introductions here
Hello everyone, I have come to get help fixing a TV I got for free.Leave a comment:
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