Panasonic 42 Inch takes 15 seconds to come on

If no picture and sound I would suspect the main board.

Please remove any HDMI cables connected to the TV. Then test a different power source. If the problem persists, then we recommend you locate an authorized service center.

1.Check the device's battery level for at least two bars of strength.
2.If the battery level is low, charge the battery.
3.If the issue is not resolved, remove the back cover.
4.Remove the battery.
5.Wait 10 seconds.
6.Press and hold the W key.
7.While pressing down the W key, re-insert the battery.
•The device restarts and after approximately 15 seconds, the 'Recovery' screen appears
•Release the power button but *continue holding the home button*, for another 30 seconds.
Step
Thanks

10 blinks of standby light with Panasonic Plasma indicates:
10 blinks Sub 5v SOS / Main 3v SOS DG Board
DTV 9v SOS / Tuner Power SOS

For more details visit the site named [Electro-help" The keyword to search is "Electronicshelponline"

No--this is called a PDP or plasma display panel and no two (even same brand) can be interchanged.

The cost of a Panel exceeds the cost of a new set--broken screen=fatal issue.

I unpluged mine and the light was still blinking when it was unpluged. I thought that was weird. So I pluged it back in and just heald the power button in untill the light went out. It went out within ten seconds. I pushed the power button again and the tv went on. WOOHOO!!! Just needed reset, I guess.

it is likely the power supply board in the back of the tv. these are a huge problem. I fixed mine for $15 by taking it apart and taking the board to a repair shop. new cap on the board fixed it.

i have the same problem on my tv and i call to bestbuy since the tv is only 2months so still on the manufactures warranty the problem is SC Board shorted, and they replaced the sc board.

Try to replace the Main Power Supply board first.

TURN OFF THE MAINS AND THEN SWITCH IT BACK ON