I've had this model is 2013. it has survived 2 intercontinental house shifts. The more standard problem with the 8100 is the cienma filter which cycles up during power up. The Gears that drive the filter tends to get damaged and then the proj wont turn on.
I would try to isolate the problem. if its happening all the time, irrespective of source, cable or input, it could be a panel problem. IF its more occasional issue, it would look at the source and cables as culprits. Projectors are very power senstive, I assume you are feeding clean power to it.
Its unlikely that the lamp is the culprit unless you did not put a genuine Replacement lamp. those could have different electrical or thermal characteristics which could potentially play havoc with the sensors and the heat with the panels itself.