I'm wondering if anyone knows how to change a bulb in a cold light head. I bought a Beseler 45 MXII on e-Bay and the bulb was broken during shipping. So, given the cost of a new bulb, I instead bought an Aristo cold light head (e-Bay) with a HI V54 lamp. It does not fit onto my Beseler. So I want to change out the bulbs but both units appear to be pretty well self-contained. Does the bulb just pull out of the unit? Or does the unit need to be opened? Any help is greatly appreciated.