Richard, based on what you have indicated, I would suspect the voltage regulator is defective. A voltage regulator is designed to maintain a constant voltage through circuitry that smooths out variations in line (AC) voltage so lamp color doesn't shift during exposure. If you can physically see the lamp intensity changing on 'turn on,' I would suspect the regulator is not functioning properly. Check the output of the regulator with a voltmeter to see that the ouput is, I would guess 12 volts. It should instantly (within a few milliseconds) reach proper voltage and maintain that without varying. From what you are saying I would expect that the voltmeter would see something like 10 or so volts finally stabilizing at 12 volts.
Sure sounds to me like the regulator is bad. I have a voltage regulator on a Vivitar VI and will try and get some possible data today.
Edit: I just checked the Vivitar and mine is voltage stabilizer. It puts out 19.8 VAC to the lamphead. I was thinking an AC to DC voltage regulator in the previous discussion.
Is the stabilizer a Durst 'matched' unit (EST 305 (N)) or is it an aftermarket generic unit?
Last edited by Fred Aspen; 01-02-2013 at 10:26 AM. Click to view previous post history.