I have recently resolved my blinking green light without replacing ****. I was told the ballast, DM board, capacitors, power board, lamp connection.
I had replaced the lamp and the light started. I searched for four months on threads and forums. It seems everyone has the same issue after the lamp is replaced or a power out.. I found one thread out of hundreds suggesting a "factory reset" different from the reset on the front panel. Maybe the software is corrupt or the whole thing needs a reset to default with a new lamp. What ever the case this did it for me. I am thinking yours is a mitsu too so maybe.
Try this when your tv powers up in those 15-30 seconds hit "Menu 1,2,3" on your original remote. This takes you to the factory settings. Select "initiate factory reset". This corrected my 52" Mitsu. I was about to take it apart for the 4th time and start replacing caps. Thank God I didn't.
Post your results.