As the title states my projector has decided to randomly flicker. I know it is the PJ because it has the problem on test patterns that are built into the projector with no source attached. If I tap the side of the PJ, it stops. Also, it only starts if I'm using it for a few hours, in the first few hours it doesn't happen. I've never seen this before and only have 1500 hours on the PJ and bulb. I'm thinking that the bulb is going prematurely. Anyone else ever seen this? Projector is a Mitsubishi HC4000 connected to an APC UPS to protect the bulb. Any other thoughts as to what could be the cause other than the bulb?