61mp1 nec plasma keeps shutting down after 5 minutes, when switch on picture ok

Fault to the main power supply regulator section. Either it will be a separate board, or the part of main board. Check and replace damaged component/s at its main power regulator [SMPS] section circuit. Contact any service technician. If you wish to get some details; check the site linked here. Pull up older posts.
http://electronicshelponline.blogspot.com/
It will be best to replace the power supply regulator board as card basis rather than making "Surgery" to it; which usually will make loss for both money and time. Even though you can make it right, it will cost around an amount equal to the cost of a new board; including the cost of (spare parts + service charge) More to say, most of the spare parts to it will be difficult to get from open electronic spare part market. This is true to most of the flat panel TV power supply boards; irrespective of its brand and screen size.

cant find signal with or without cable box

Shut off your projector by swith on the back near the AV inputs, leave it off for about five minutes. Then switch it back on, manually press the power button, let it start for about 5-10 seconds then continue to hold power button until picture appears. It worked for me, good luck to all.

Its the power supply board. If you cant get the whole board, check your transistors theyre most likely FSXXX-X (part #). Replacing them should solve the problem. And they're only about a dollar each so youll save a bunch too but it requires a little more work.

Ryan

I have a 61MP1 that wont turn on. I get the green flashing light to signal power but nothing happens with the plasma. You seem to know a fair bit. A guy in UK said he'd supply a new power board for $500 but wants my old one in return. Sounds like it might be something I can fix here. Any suggestions. Barry

Has anyone figured this issue out? Im really hurting without a tv,

Hi to all, My 42" Panasonic plasma have the same problem. It turned itself off and now red light flashes 7 times, than after short pause 7 times again. And so on. Any ideas what is wrong??

As you say that it works for 5-10 minutes it clearly indicates that all parts are 100% ok. problem is loose contact mostly in power supply& IF IT IS OK then loose contact in horizontal section. Good luck.

This sounds like the shutdown circuit is shutting down the TV due to an over current condition. This overcurrent condition is caused by a component in the HV section drawing excessive current. the 5 blinks is a visual indication of the problem.