Screen is blue with lighter blue lined flashing

Model is Mitsubishi WD-62725?

The other question is does it do it on tuner and REAR inputs?

go in menu there should b options in there to set it to cable tv instead u have the option set on air or antenna instead of cable

Take the front screen off and dust the inside mirrors

There's a recessed "SYSTEM RESET" button on the front panel.  Use something with a point to press it and wait.
http://www.mitsubishi-tv.com/pdf/ownersguides/WD-57734.pdf

just happened to us, we unplugged in from the surge protector and plugged it in the regular wall outlet and were able to get the tv to come on, don't know why, but it worked

Call Encompass Parts 1800-638-3328 or look them up online they list your TV as well as Service Manual and Keep in Mind just because Light Engine was replaced 3 months ago does not mean it cannot be same Problem so if you have any warranty on it replace it again!

I had the same problem and I found that it was 2 caps on the power supply board. I had both caps replaced and it worked perfect. While it is apart see if any other caps are bad( if they are puffed up in the center they are bad).

you have either a defcetive signal pwb, FMT pwb or light engine. Does the menus appear clear when you press menu?

Good Day;

It sounds like you have a lack of signal; 1. reset TV by unplugging TV & signal sources from wall for at least 5 minutes then plug back in, 2. Turn all eguipment on such as cable box, dvd & etc, then change the inputs from your TV's remote, if still no pix,only blue.

Good Luck.

Sounds like one of your colors are missing. make sure all colors are lit, Blue, Red, Green