It sounds like it's probably the power supply, or it could possibly be the lamp assembly malfunctioned. Mitsubishi does not supply service numbers for consumers, but their email support is very good. A tech usually calls back within 24 hours. If you did originally purchase an extended warranty, i would recommend still calling the warranty number, as they will probably try to help you out.
MEVSA WARRANTY DEPARTMENT
Mitsubishi Extended Warranty Programs