Anonymous posted an answer for this Optoma H30 Multimedia Projector:
"I have an optoma hd72 did the same thing. I pulled the bulb out and used a can of air/dust..."
Anonymous posted an answer for this Optoma HD70 DLP Projector:
"I HAVE A HD72 DOING THE SAME THING, I PUT IT IN HIGH ALTITUDE MODE(WHICH MAKES THE FAN RUN..."