Why won't it turn on?

Check your power supply for correct power readings.

One of two things a clogged up CPU fan and block may be the contributor over heated and possibly fried the board. The other issue may be a bad power supply unit, replace the unit and reboot. John

I am having the exact same problem with my 47ZV650U, what was you solution

You will need to take it to a repair shop. Most likely you have a bad seine board or possibly a power supply issue.

Possibly not.. in this case with the 42HL167, the CPU pcb (most commonly referred to the SEINE PCB) is having issues booting and just isn't starting up.

My friend gave me his 42HL167 after this problem started after a power event during a storm and I managed to fix it by reloading the firmware.

I posted instructions on my website at:

http://www.benjammin.net/www/pages/techtips/Toshiba-Regza-42HL167.html

Once I figured out some of the facts, it was a breeze...

I posted this elsewhere here since there's so many duplicate threads... trying the firmware update is simple, so it's worth trying that first since the case doesn't need to be opened.

-Ben

I had the same problem with my 50HP95 Toshiba Plasma TV. It would not turn on. I read online that if you unplug a connection on my TV and it turns on, it is a bad Seine board. I could not find this Seine board anywhere online. It was either out of stock or no longer available. The TV is just 5 year old. Why would they discontinue parts for it? Then I saw a video on You Tube where someone unplugged a connection in the back of his TV to fix problem. I decided to try it. I took the back off, unplugged a connection numbered PJ63A and the TV works again. So far so good. I downloaded the Service manual for this TV to find where PJ63A was.
I also called Toshiba Tech Dept. to find out if there was a chance I can cause further damage to my TV. They had no idea.

in protective mode the tv does not turn on and light is blinking, typically we must proceed by elimination as some faulty sections are preventing the tv to switch on. unplug the output power connectors from the power supply until the latter stop clicking. if it is still clicking after every of the output rail have been disconnected, then the power supply itself is faulty.

but anyway 3 circuit boards seems a lot to be replaced in a row.

hope this helps!

Turn off set, unplug power. Remove back cover. On brown circuit board left of center, unplug connector PJ63A. Plug in power, but don't electrocute yourself! If you no longer get the continuously blinking red light, hit the power button. If it comes on, the SEINE module is bad and must be replaced.

This answer is for sjmhan: It sounds like you have a fault on the power supply board of the tv. Please before you open up your tv find out how to take basic precautions against electrical shock and how to discharge capacitors safely. First check if there is a glass fuse inside of the set and if it has blown replace it with one of the same rating. If you replace the fuse and it blows straight away or it still does not come on then it could be quite a few things. Either a faulty resistor or diode or voltage regulator or even the mains transformer itself. One word of warning: NEVER toucch any of the pins of the transformer as this cannot be tested directly without specialist equipment. If you find that it all is too complicated for you then dont feel like you have failed just re-assemble it and find a competant technician. Good luck.

Kimlong: I think you have a faulty component on the power supply board most likely a faulty diode. If you can check this for yourself otherwise find a competant technician. Hope this helps.