Thank You very much for your reply. Much appreciated. Or maybe they just know what the problem usually is, given that they make the fixture and deal with its faults every day. I don't think I've ever had advice from a manufacturer tech support that is motivated by parts sales, Martin or any other. A lot of standard advice for fixing modern LED units is gonna be a PCB swap rather than component level fault finding in the same way that a car mechanic no longer overhauls assemblies but rather swaps them out for whole new ones. I do work at component level, but in order to get working fixtures back on the road in a reasonable time there is a lot of board level swaps, leaving dead PCBs to be fixed during downtime. If you ask a manufacturer service tech what they do, you'll usually get a "We just swap the board." answer. As it says in the user manual that the BETE is a sensor error, not an actual temperature error, then presumably the problem lies in the sensor circuit somewhere. This could be anywhere from the sensor, all the way back to the processor. You could hunt down the fault and attempt to rectify it at component level, depending on skills and tool availability but this comes at the cost of time and the risk that you may not be able to find/fix some tiny issue. However, a lot of the time it's more cost effective for a business to just swap a part out and move on. If you want to verify the fault and Martin's advice, then swap out the parts they suggest with known working ones from another fixture. Then you can assess if you want to buy a new part or use a donor fixture etc. I started a series about this recently: http://www.onstageli...ice-and-repair/ and http://www.onstageli...ir-maintenance/. When the next in the series comes out, it will outline a method by which you can avoid buying an LED PCB costing hundreds of pounds, just to replace a single R2 Wash LED chip. Obviously, that isn't gonna fix your Quantum Profile but all these topics are highly relevant at the moment, and the reason I've started the series of articles. :)