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Crumbtrail TV Forums: TV Equipment: TV Repair Forum:
Sharp LC70LE640U power issue...

 

 


winfab
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Apr 6, 2017, 11:20 PM

Post #1 of 4 (978 views)
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Sharp LC70LE640U power issue... Can't Post

First of all, I am new to the site. My name is Jay, and I'm in Southwest Ontario, Canada. I have been an automotive electrical technician for 20+ years, and have recently made the switch to electrician.

I own a Sharp LC70LE640U which was purchased brand new I believe back in end of 2012-ish. It has worked great all these years, except for the last week. I had an issue where the TV would not shut off. My Harmony remote or the original Sharp remote. Walked up and pressed the PWR button on the side, nothing. Pressed the PWR button once more, and the set finally powered down.

Well, the next day after work, went to turn the set on, and nothing. No flashing logo LED telling me the Sharp error codes, nothing. Was like the set was unplugged from AC power.

After work the next day, I called a friend over to help me get it down from the wall. Opened it up, expecting to see bulging caps or something. Everything looked perfect! So, I plugged it back in, and it fired up! Still no response from the remote, buttons on the side, etc. The panel works fine, HDMI input still works, etc.

I haven't disassembled the television a second time to actually test the secondary DC voltages from the power supply, thought I would post this issue on here to see if anyone has seen it, or has any advice.

Thanks!

Jay


(This post was edited by winfab on Apr 7, 2017, 12:36 AM)



winfab
New User

Apr 7, 2017, 12:52 AM

Post #2 of 4 (962 views)
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Re: [winfab] Sharp LC70LE640U power issue... [In reply to] Can't Post

Should mention that the television, when I can get it to turn on by leaving it unplugged for a few hours, still works perfectly. Picture and backlight, etc are unaffected by this issue. HDMI input still works as before with no random glitches such as picture cutout, lines across screen, etc.

I have a BellTV satellite receiver and an Onkyo receiver hooked to the television. Same setup since I purchased the set originally, no changes to equipment.


winfab
New User

Apr 10, 2017, 7:41 PM

Post #3 of 4 (928 views)
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Re: [winfab] Sharp LC70LE640U power issue... [In reply to] Can't Post

This issue has been resolved. One of the components I had connected to my Onkyo receiver had an abnormally high amount of voltage through the HDMI cable.

This was feeding back through the Onkyo, and eventually back to the television. Seems the mainboard of the Sharp doesn't like voltage coming back through the HDMI, and it must have been locking up the eprom on the mainboard. With the faulty component disconnected, the television works as normal.

Thought I would post the solution up here just so there's not another dead end thread.

Jay
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LouF
New User

Apr 11, 2017, 4:54 AM

Post #4 of 4 (924 views)
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Re: [winfab] Sharp LC70LE640U power issue... [In reply to] Can't Post

Not that I specifically can be of any help here, but I do have a similar abnormality.

I once made an extension cord for a television that I wanted I be just the right size. The lamp cord had thick insulation, and was too thick to properly fit in the replacement plug, so I shaved some down. It fit, but it was not good. After some time while doing something else, I noticed I was getting a shock from my coax cables. I immediately suspected the crappy job I did with the plug, unplugged the TV, and it was gone. I found a better fitting plug, and everything went back to OK. Needless to say, somehow there was some current leakage.

I was a bit surprised the breaker never tripped, and these are the exact situations that arc-fault breakers are implemented. Especially since there is a much higher amount of electronic devices used these days, with *many* chances inside these devices.

 
 
 


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