42inch sonya flat sreen tv turn on I get sound I could see the sreen alittle bit but its dark

Change tv, plasma have a life span of 8 to 15 years. Your's is at the end of life span.

MY VIZIO E701i-A3 has sound but no video /back light on /screen only show dark blue sreen please tell me if it repairable or not?

Can it be heard with sound off and describe the sound a bit, buzz or high pitched sound? Not unusual for the front screen unit to make a slight buzz but I gather this is loud.

Hello,

Problem is in either power supply or the Y-Sustain board.

The Y-Sustain is a relatively large board out of which go connections to the side of the display; it's therefore closer to either the left or the right side of the display, has at least one rather large heat sink on it and fat power cables connecting it to the main power supply.

Often there are fuses on that board - one or more. Check those.

this problem is from your tv mainboard, change it with new one

As your problem look like your tv Panel get weak need to replaced.

sounds like your actual tv tubes blew causing no picture usually more expensive to fix than to just buy a new tv bad luck

It could be a Power supply problem or a Main Board problem. Best to have a Pro look at it for you.

The tv plays fine my sreen is cracked on my Sony 42inch screen can some one help me.

It sounds like it's the inverter panel which lites the lcd back light.
If it's under warranty, try to replace it, or take it in for svc.