Upon powering on my Toshiba 36" I get the normal.......

crackling sounds and nothing happens, no picture no sound but if the set sits for 24-48 hours and I try again, the tv will work perfectly when I turn it on. I have since sent the tv to the repair shop and by the time they get to it, it works and they can't seem to find anything wrong with it. The first time I sent the set in about 2 weeks ago they repaired it and charged me around $200.00 and sent it back to me and the next day I tried to power it on and nothing happened. I called them back and they picked it up and after 5 more days of waiting I called them and they said they can't find anything wrong with it. So I got the set back and after turning it off, I checked it and it did not work again. All I get is an attempt to power up but falls short for some reason. I also get the flashing red power light that will flash/blink but thats all I get. But if I wait a couple of days and not touch it, it will work fine when I turn the set on. Very confusing. Please help me.