I've got a 73742 that had the main board go out a few months after getting it a bit over a year ago.
Since then, on some few occasions about every 3 months or so, the set powers up to a fast blinking green light. The fix is to unplug it for a few minutes and then plug it back in. I know that isn't a real 'fix', but it is one of those problems a tech probably couldn't find unless it did it while testing. Fortunately for me, I bought a long extended warranty so at some point I'll be able to get it fixed right.
BTW, I'm now on month 15 or 16 with the original lamp. The set is run about 8 hours a day almost every day. That is a huge improvement in life compared to my old JVC HD-ILA, best it ever did was about 10 months on a lamp.