Sanyo dp42746 plazma tv help

[needles-2]

Hello  I have a problem could you help me?
I have a sanyo model dp42746 when I press the power button I hear a click in the back but no screen
I am limited to changing boards out and some basic repairs I have replaced the power board no help, a green light on the power board flashes 12 times is this some kind of code? Please any help would be appreciated Thank you Bill