PT-45LC12 wont power up

Ballast Board ,it is what turns Lamp on! Call Encompass Parts for Part or look them up online they have website. Call 1-800-638-3328 Ok I looked it up Part# is LSEB3062A1 which showed No Longer avaliable,So try UED 1-800-648-6657 and Look on E-Bay under Electronics For Ballast Board.

It looks like a problem with a tube (projector light) I suspect the green one. Pay attention to flickering on the lights and post me the results. 

With power on, hold down VOL minus button on projection display and hold down the PIP or SPLIT button (try both) on the remote simultaneously for more than 5 seconds.

If it si the Temp Lamp, the unit is indicating overheating. Check to see filter is clean and vents are not obstructed.

having the same problem, after some research, came across this: http://www.fixya.com/support/t142873-panasonic_pt40lc12_blinking_green_power

Not a tech, so I'm going to look into it further on how hard this is to do.

yup.
cut it and jump the wires.

you have to remove all the screws on the rear base of the set,and underneath the speaker grilles,then separate the front and back.

When the lamp flashes 4 times this is what the error code means IC 2301 pin 11 has detected an LCD error which is caused by an error in the LCD power CBA. which means the lamp voltage has become more than 130 volts or less than 30 volts. Or the lamp current is more than 5 amps, or the lamp is cracked. Its one of thos 3 reasons that will make the lamp indicator blink 4 times. Hope this helps. If you need the service manual for this model you can get one emailed to you from the following link.
http://servicemanuals.vstore.ca/

disconnect the power cord overnight try it if ok change power cord cheers

More like lamp failure. Could be other things of course but start with the lamp cause it will need it anyway if has been a couple years.
Projection TV makers charge an arm and a leg for their replacement lamps. They make it easy to do but as a result the custom lamp assy is expensive. The trick is to just buy the bulb for your model TV from any number of us aftermarket sources at a fraction of the lamp price and install it in the old lamp yourself. really easy. Some models are real bulb hogs though. Look them up on the net (include the word complaint or repair) before you buy, or you might be sorry. Many class action lawsuits out there - even against some of the name brand makers.
Hope ya fix it!