Panasonic TH42PZ85B troubleshooting standby light flashing red and TV will not come on line?

What does it mean when the red standby light on my TV is flashing? ... If the television switches on, then there may be an issue either with the remote control or the remote sensor on the set. The best way to test this is to take the remote control to a retailer or service centre and test the remote on another product.
https://support-uk.panasonic.eu/app/answers/detail/a_id/3825/~/what-does-it-mean-when-the-red-standby-light-on-my-tv-is-flashing%3F

see the videos:
https://www.youtube.com/watch?v=D8-xIIIK1mY

https://www.youtube.com/watch?v=-2P-G9g0mNU

chk this link....

http://www.techlore.com/forum/thread/19563/Pioneer-SD-533HD5-Green-light-flashes-then-back-to-standby/

was that capacitor damaged?

My baird JO47 tv is stuck on standby - Digital TV - Streaming ...

www.tomsguide.com/forum/55998-4-baird-jo47-stuck-standby

Dec 17, 2012 - 4 posts - ‎2 authors
My Baird JO47 tv is stuck on standby and won't come off. ... I have a panasonic 50" TV it will not turn on no green light or standby red light ... Forum; my tv standby light keeps flashing blue on and off and won't switch on Forum ...

Baird JO47 Stuck on Standby ' Electronics Forum (Circuits ...

this is a simple capacitor fix at your local tv guy..should be 100 to $150 max

How many times do the standby light flashes at a time? Count this. These flashes are fault indications. Check this to know more about blinking codes to Panasonic LCD and Plasma displays.

set is trying to move from standby to power supply on and not making it, No model indicated so best advice is take to some shop and get an estimate.

Hard to troubleshoot with just this info, the red light can be helpful if its 10 blinks repeating over and over replace the power supply first then the A board. Voltages check on the power supply would narrow down the culprit.
Post again if you measure the power supply voltages

I’m happy to help further over the phone at https://www.6ya.com/expert/eric_ab7c09ec01841771

yeah, should stay red when unit is turned off, indicating there's power but it's doing nothing.

Per user manual:
Solid red - power off (standby mode)
blinking red - power off (now cooling)
blinking green - power on (preparing to light lamp)
solid green - power on

Try to replace the Main Power Supply board first.