I was asked to look at a 10 year old system that was blowing lamps. SR48, DR12, Express "bread & butter" school system.
The complaint said the worklights (but none of the stage lights) were going suddenly, as soon as the lights went on. 3 different dimmers, but all on the same phase of the SR48.
I found these 1000W lamps in the (non-ETC) work-lights, some Osram, some no-name. The 3 well toasted ones look like a severe over-voltage - just as the drama teacher said.
Now 3 - 1KW fixtures in a 2400W dimmer is bad news, but it shouldn't cause this. However, I couldn't find anything else wrong. The rack didn't report any errors, voltages nominal at both the CEM and at the fixtures. I replaced the lamps with 500W ones and everything seems fine.
What is happening?
