Hi there guys,
I would like to learn more about the ballast circuitry used inside the moving head lights. Lately I have been getting these kind of units in for service. I couldn't find any resource online schematics or workings of these ballast circuits.
I have noticed that the ballast circuit destructs if the power is applied and the lamp's filament happens to be open. I couldn't check the filament of these bulbs with a DMM prior :S. Would a new bulb become faulty if the ballast circuit had any issues?
Anyway I was hoping that you could direct me to some info on these types of ballast circuits.

Thanks so much for the help.

 

Looks like a switchmode PSU, what voltage are the bulbs , and what mains input voltage is it?

 

Looks like a switchmode PSU, what voltage are the bulbs , and what mains input voltage is it?

Yes it does look similar to a SMPS with four MOSFETS (full bridge sort of thing). The input to the board is rectified mains around 380V. The bulb which the client gave me didn't have much info on it, but a online search for similar bulbs shows that its around 85V