Couple of good tips there- ta. Not actually mine (belongs to a bunch I work for occasionally), if I get another half hour free with it I'll give them a try.EDIT There's at least one thermal switch/fuse on the main heatsink- doesn't look like a one-shot and its showing continuity so still suspicious of the PSU Indeed it is- nice little beasts, no idea how many hours but nowhere near enough to hit the 50,000 quoted :) Hi, Thanks for confirming. The Rogue R1 Spot has electronic dimming / strobe so this may then point to the drive circuitry of the LED being at fault or perhaps an overtemp error causing it not to turn the LED on. It's all potentially repairable. If you would like to book the unit in for assessment to determine exactly what is at fault, or if you need any further help just let me know. Kind regards, Dennis Ta. Not actually mine (company I work for occasionally) but will pass that on. Yeah the DMX chart mentions dimmer but I'm sure the things sit there glowing all the time when they're powered up (wonder if the profile on the disco desk they have is driving the shutter rather than the dimmer.......)