Hi : have a D40 that shuts itself off after it had been on at high power for about 20 minutes.
After a few minutes it turns itself back on.
It does not do any of the " high temp / over temp" behaviors.
It is totally off- nothing on displays, no response to fixture control buttons.
Ambient temperature is not an issue ( well ventilated, air conditioned space.
Fixture is apx 9 years old, but gently used.
Any suggestions ?