Mitsubishi LT-46148 flashing light - LG 50PG20 50 in. Plasma HDTV

Service manual are released to repair shops and not really available to the public.

Nancy, you may, if you would, get information about the TV by getting and reading the manual, here (below):

https://www.manualslib.com/manual/296300/Mitsubishi-Lt-40164.html

Hey it sounds like u have did everything, so check and make sure u downloaded the right firmware on a good USB drive such as a 4GB and make sure format it with Fat32 before u download. Have seen that before with jump drive device and follow directions from Mfg website. If does not work then the CPU or Eprom has been corrupted and main board needs replacing.

Continuously blinking green indicates unit is booting, if that is all it does, the most likely problem is with the MAIN PWB.
Part# 934C335003
see following website:
http://search.store.yahoo.net/yhst-49649682161378/cgi-bin/nsearch?query=934C335003&searchsubmit=Go&vwcatalog=yhst-49649682161378&.autodone=http%3A%2F%2Fstore.tv-repair-service-salinas.com%2Find.html

also try this website:
https://www.ued.net/ued/searchResults.jsp

Go to the Mitsubishi website, download the upgrade, save it on a flash drive, plug it into your TV, follow directions provided on the website. If you have done this previously, check on website to see if there are any other upgrades, if not, repeat the previous one. This has worked for us. Good luck! Also where you bought the TV may be able to assist you. Mitsubishi will send you the upgrade on a flash drive for a charge.

Mitsubishi LT46164 has a known issue developing on the main board that causes what you describe (and other things):

http://www.coppelltvrepair.com/p/1635/repair-service-for-mitsubishi-main-board-934c374002-causing-dead-tv-blinking-loop-no-hdmi-no-audio-etc-problems

These blinks (flashes) are fault indication. By the number of blinks occur at one time switch ON, you can get an idea about the faulty circuit stage inside the TV. Count the blinks occur at one time switch ON, carefully. Do it once again, and make sure about the number of blinks. If the flashes are continious, non-stop, the main system control IC should be suspected. If you wish to get more details, check the site linked here. It has blinking codes detail to many brand TVs. Pull up older posts. Check the site in 'Mosaic' view. It will make search easy. Electro help

sound like bad turn signal switch.

Hello. I was in a live session with you earlier and it seems like you accidentally closed the window. Does the tv tv click on momentarily before it shuts off and starts blinking?

It is possible that you have a bad power supply, or the TV has been hit by a small power surge and if you unplug the set from the wall for 40Min., it will rest back to normal.