Sanyo p42840-06 channel menu comes on then goes off led power stays on.

LCD & LED TV Repair - No Image & Blank Black Screen ...

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https://www.youtube.com/watch?v=xUzCLgoSPGM
Sep 15, 2014 - Uploaded by ShopJimmy.com
LED & LCD TV How to Diagnose Symptom of No Image on the ...the the tv turns on but there is no picture or sound and I can't seem to fix it the .... +tbones11234 I have the same on myHisense 55" TV,what did you ... The problem is when i turned it on it shows on the screen the sony logo three times then its ...

TV with Black Blank Screen Repair How to Troubleshoot ...

? 3:16
https://www.youtube.com/watch?v=kFdVi2ejfzA
May 8, 2014 - Uploaded by ShopJimmy.com
TV Repair Help for a TV With a Black No Image on the Screen ...Click Here to BUY TV REPAIR P... ... I Have a Hisense Tv in My Screen Is Not Working Right The brightness is ... Hi my TV shows the picture for a moment and then goes .... here the sounds but you cant see nothing and a sanyo flat screene.

well I cant be sure because you didn't supply a model number but some models of sanyo's allow one to parental lock the menu bar via password , this prevents kids/others from accessing the settings pages and the channel lock functions , also the key on your remote for menu might have failed as well could be another possibility .
if you have permission of the owner of the set one can preform a master reset if passcode is no longer known , then all your favorites and channels would need to be restored back in

Double check all your connections.

It sounds that the main digital board to this TV is faulty. Contact any service technician.

Replace the Main board if your not hearing any audio from the set.

Need s to be replaced the main board.

We have a similar problem when changing channels/surfing, the TV will begin to power cycle, until you unplug THE CABLE TV input, then it will turn on again and stay on as you rehook the cable and change channels....till it decides to do it again, DTV channels seem to trip it up, but not sure....if I leave it on the same channel it will run for days. Yep and the cable TV is grounded outside

to reset the whole tv press menu 1 2 3 enter