When I was cleaning my Micron today I realized 2 things, which I don´t think should happen: When I press the trigger just for air, air seems to go into the cup. Slowly, so it takes a bit till a single bubble builds up, but still that means all the paint is pushed back into the cup. After cleaning I just sprayed pure water through the gun and I could see that the water is not comming out evenly when the trigger is pulled back just a little and I could here it pulsing. Needle and nozzle are as clean as I could get them and they look good. I never dropped them or hit the canvas with it. Water is thinner than paint ever gets, so too thick paint shouldn't be the problem. Tested airpressure from 1.5-2 bar, but the same result. I wasn't using the gun for about 5 years now, but while using it I didn't really feel it works bad. The only thing I can think of is the o-ring. Could that be the reason? Or any other ideas?