Panasonic tv model th-42px 8b when switched on turns the green LED on and turns red immediately and continue to blink

SOURCE: Panasonic TH-42PX60U plasma TV: red blinking light

are you using a PC to feed a signal or maybe a cable with an adapter?
I had the same issue when I used one of the rear HDMI ports to show a PC display. Apparently there is a software difference between the rear and side/front ports. Inputting the PC through the side HDMI port has solved the problem for me (so far!)

SOURCE: red led flashes. when i try to turn tv on it shuts

There should be a number of flashes that you can count. This is an error code. It will flash a number of times and stop. Again, Flash a number of times and stop. Contact a repair shop that is familiar with panasonic and have them to check it out.

SOURCE: Panasonic plasma TV model TH-42PD60U won't turn on

I had this problem in 2007 / 2008 here is what happened to me. Jan 09, 2008 - I also have brought the unit to the authorized Panasonic repair facility and the problem is a failure in the P-board which is the power supply board. The P-board needs to be replaced. The repair will cost $475 plus tax. $250 is for labor. The unit was nop more than two months out of warranty. This does not speak well for Panasonic. I have been researching the problem and it looks like this has happened to many of the Panasonic plasma TVs.
Jun 14, 2008 - As an update to my problem with the failed P board. Contacted Panasonic Service and talked to a customer service representative. I told them how I have purchased many Panasonic products and how unhappy I was with the failure of the product. They proposed paying the labor cost of $250 and I would pay for the part. I just hope it does not happen again.

SOURCE: Panasonic TH-50PZ80U tv, error- 2 blinks

1. Reseating the connector P25 may solve the problem. If it does not.
2. Unplug the unit andd disconnect the connectors A5, A6, and A7. Apply power to the TV. If a White screen comes up and all voltages check normal, replace the P board.
3. If the TV stays on after isolating the SC board, then replace the SC board and the D board; it is likely that the fuse on the D board is blown.

SOURCE: TH-50PZ80U POWER INDICATOR LIGHT KEEPS BLINKING

Power board it dead,take the tv aparts.Check for Capacitors parts for puff up or burst open.Know how to solders?replaced these capacitors in the power board.Or replaced the whole power board.Tries Shopjimmy.com,Ebay.com.