On 4/10/07, alan smith wrote: > Just a followup to some of the comments. > > 1. Removing the 'dimmed' LED's and replacing fixes the issue of course. When they take the LEDs out of the circuit to replace, he tested them out of circuit and they remained dim. So its not the circuit per say but the part. The part is damaged, but still uncertain wether this is from your circuit or not. > 2. Current spec has it max If of 50mA. I am running them at 35mA, way below the rated spec. Could that be a misprint? > 3. I did confirm they measured the voltage drop across the curren limit resistor of a good circuit vs bad circuit, and there was no real difference...ie....it didnt all of a sudden change in is current draw/voltage drop. Just went....dim. Could there be an inductive event when the LEDs are turned off? I would think that would hit the transistor more than the LED, but I don't know your circuit, or physical implementation. > Bad solder...por ESD protection. Yes....could be. The CM is a long time friend of the clients, but has been getting burned by him on more than one occasion. They do not handle the boards carefully, its a manufacturing enviroment, not clean.....nary a wrist strap, etc. Unlikely to kill leds like that. > But they have been building LED based stuff for a number of years, they have seen bad batches of LEDs before. I suggested sending the bad LEDs back to the factory for analysis but not sure how far that will go...ie...getting the chinese factory to even evaluate. They only use around 50K /yr so not a huge user. About the time we get permanent colonies on neptune... -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist