I have the JVC 46' flatscreen, and it want come on. I press the power button and the blue light comes on (as if the tv was about to come on) but then it starts blinking.

Hello,

The issue you describe is consistent with a power supply board issue. This is the board where the AC goes to. This problem may have occurred as a result of irregular power supply, or excess power supply or power surge.

The TV is receiving current but cannot circulate or transfer the current to other necessary part of the TV because of the defective power supply board.

I do not think it needs replacement, rather some defective capacitors are causing this issue.
Open unit up and take a look at the power supply board.You will probably see one or more electrolytic filter capacitors that are bulged up in the top-not perfectly flat like the others.

The value of these capacitors will be different, most likely they will be somewhere around-820 to 2200uF/25 V( or /10V sometimes)

You can replace them with same values but I would recommend the voltage rating to be higher(like 35V for an original 25V) for reliability purposes.

What happens is,these bulged top capacitors will cause a low and unfiltered DC voltage=main board will malfunction(the relay will keep clicking until the caps are holding enough charge to bring the voltage up over a threshold point).

You can buy these capacitors at any Fry's or Radioshack store or you can order them online at vendors like "mcmelectronics.com"(look for electrolytic capacitors).
After replacing these capacitor(capacitors) most likely the normal operation will be restored.

Note: There may be also some other causes for this symptom ,like a defective T con board ,or main board,but the bulged top capacitors are the most common cause for this issue.

If you don't know about TV repairers, take the TV to the nearest repairman to fix the fault for you. Also, note that TV stores a lot of current, so wait a while before opening the TV back cover.

I hope this helps.

Good luck.

Have you had the tv working before?

It sounds like the input/source is not correct.
Is there a button on the tv (or remote) called Input or Source?

Try pushing that.
If you're trying to watch cable tv, make sure the source is set to cable.
If trying to watch a move, make sure it's set to either HDMI or aux.

Hope that's the problem, and not anything more serious!
Have a good day :)