Why does my sharpe tv switch off every three hours and then restart on its own

Firstly check the mains plug,and its connections including fuse.
Other than that it would suggest that the internal power supply is collapsing causing the problem, if this is the problem a specialist repair is required.DO NOT under any circumstances try and repair it yourself as lethal voltages are present.

Remove all the connectors to the main boards and then plug them back in, this can be caused by a poor connection between boards.

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Top 298 Complaints and Reviews about Sharp TVs ' Page 2

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I bought an 80" top of the line Sharp Aquos TV (MSRP $5959.00). ... I have the 20"Sharp flat panel TV with easel back stand. .... is to where you live, because in mystate (Louisiana), they're all at least a three hour drive away. ... Purchased a Sharp 70" model #LC70LE750U on 1/23/14 from Conn's and Saturday (11/28/15) ...

Tries tv unplug replug the tv back about an hour later,might resetting the tv back factory setting and should work again.Still have the problems,the main board it is shorted and dead require changing.The main board that board were the incoming broadcasting signal wire plug into it.U have some basic machanic skills like take things a parts and putting it back together again.Should have no problems change this board at all..Tried websites like Shopjimmy.com,eBay.com to buy a refurbish main board for the replacement.

Hello
Three digit universal remote code for Sharp TV are:
004/ 009/ 079/ 095/ 111/ 112/ 114/ 122/ 123/ 124/ 173
Four difit universal remote code for Sharp tv are:-
0079 0123 0063 0020 0004 0009 0226 0266 0006 0095 0122

Direct Code Entry

1. Press and hold the SETUP button until the red indicator stays on, then release the SETUP button.
2. Press and release the desired Mode button (TV, VCR, etc.). The red indicator blinks, then stays lit.
3. Enter the 4 digit code from the code tables. Note: after a valid code entry, the red indicator turns off. For an invalid code, the red indicator flashes.
4. With your device on, press CHANNEL UP. If the device responds, no further programming is required. Note: If some buttons do not operate your device, try one of the other codes for your brand.

NB: Switch OFF and switch ON your TV with its front panel power ON/OFF switch each time before trying an other code.

I have two 46" Sharp Aquos tvs,so i know this tv model well.Tv have Power and OPC LED lights flashes?Yes.Tries tv unplug,replug it back like about an hour later.The tv should be working again.This problems happen to Sharp tv alots,later on,should it happen again,just tries push the power switch on the remote again and wait the backlight will light up and tv will work again,some it will go back to Power and OPC LED lights flashes again,just push power switch again and wait,sometimes,u have to do this three or four tines to make the tv Tuner signal board to take to make the tv to work again.If u have to pushes power switches 10 or 11 times and wait and Power and OPC LED flashes lights again,it time to replace the tv Tuner signal board,that the board,where that take the tv incomming broadcasting signal cable plug into it.Tries websites like Shopjimmy.com,Ebay.com to buy a refurbish tv Tuner signal board for the replacement.

multiple signals in your area

it might mean there is an intermittent connection or cold solder joint somewhere inside the set.
But I wouldn't just settle on that.
Here are some other things to check:
1) Replace the batteries on your remote control.
2) Try resetting the logic functions on your tv by unplugging it for a minute, then plugging it back in.
3) Try covering up the infra-red receptor on the front of your TV to see if you're getting unwanted signals from the receptor. taping a piece of foil over that area is perfect. If it doesn't stop after doing these two things you'll probably need to take it to a shop.
4) If this does stop it, then look for unexpected signal sources. Have you added a remote control extender? Added a new device to your audio-video system? Changed to a new remote?
Here is what I suggest:

ONE: Give it a hard reset. Possibly the software codes in the power management are corrupted. Just unplug the tv line cord for 4 hours. That will reset everything internally to factory defaults.

TWO: Give it the old whacking test. Just bang on the cabinet in many places with your hand or fist. That will restart any cold solder joints or loose connections.

THREE: If the above procedure does not help, then you will have to call in an expert tv tech; OR just live with it and put in a line cord switch so that when it is OFF, it is really OFF.

the problem is that your cable box is putting out too low of a bandwidth to your tv and is cutting out completely. Since its all digital either its there or not. try switching to componant cables. Cable boxes only support up to 720p anyway so you wont sacrafice any quality.

Hope this helps

How many times per second does the POWER led blink? (dont worry about the OPC).

1x per second (constant, steady blink) = bad inverter/lamps
2x per second = bad power supply
3x per second = bad main board

You can buy the parts online and fix if yourself!!