FAILURE!
After just 4 or 5 days of continuous run time (120 hours max) I noticed one string of LEDs out yesterday. Funny, the night before I discovered if I had a bowl of water in the sink I could see all the LEDs lit up. Last night I saw one string of 3 was out.
120 hours is a bit short of the spec of 20,000 hours by about 99.4%
Brought it into work today to probe for the root cause, but didn't need to probe as the top of one of the LEDs had fallen off! The white ceramic and yellow mask were gone, all that was left was a thin substrate, no chip. I could make out where the wire bonds once were.
So it's a hard to call failure mode: was the LED weak from a manufacturing defect of was it just the first to go from overstress?
I could continue the life test, but at $9 a piece I'm going to exchange it and start a fresh life test.
After just 4 or 5 days of continuous run time (120 hours max) I noticed one string of LEDs out yesterday. Funny, the night before I discovered if I had a bowl of water in the sink I could see all the LEDs lit up. Last night I saw one string of 3 was out.
120 hours is a bit short of the spec of 20,000 hours by about 99.4%
Brought it into work today to probe for the root cause, but didn't need to probe as the top of one of the LEDs had fallen off! The white ceramic and yellow mask were gone, all that was left was a thin substrate, no chip. I could make out where the wire bonds once were.
So it's a hard to call failure mode: was the LED weak from a manufacturing defect of was it just the first to go from overstress?
I could continue the life test, but at $9 a piece I'm going to exchange it and start a fresh life test.