ONLY 1 of 2 things can cause this problem----
First thing to do is
remove front speaker grill--it should pull out and is secured with plastic
pegs--behind it you will find an inspection plate---
Notice the one or
two pairs of wires coming from the front keyboard
of the set---remove the inspection plate and follow the wires to the
right--you can unplug both plugs(most have two and they are marked with
letters and different sizes so you cannot get them wrong)
idea here is to remove the front keyboard
with its reset button etc
from the circuit---You will still be able to try to turn the set on
with the remote---
These sets have a Receiver that is called a DM board--(large metal box to the
left as you look from the back) and if the power goes out the green
light will blink for about 70 seconds and then go out---it is the
Receiver booting up. It is called the DM board.
If disconnecting the keyboard allows the
set to turn on--you have a bad reset switch and two choices---either
operate the set only with the remote or to remove the front screen and
get at the reset switch (it is tiny) and remove and/or replace it.
disconnecting the keyboard does not restore the set to operation---the
receiver is bad---there are 4 or more caps and some pico fuses that can
fail in that unit---Mitsubishi no longer sells or repairs these--if it
is bad and not the caps there is a company you can send the unit to and
have it repaired--if you need to know their name let me know---
call them and get a quote for repairing the receiver. There are also sites on the internet selling a kit for this repair.
If this information has helped you rate this solution as I do this here for free.
Let me know what more information you need--I am here to help.