So I got a light with XHP50s in it, and I noticed that one of the LEDs has an issue where two of the dies light up and two of them are dark. It’s the same on low, med, and high modes.
The XHP50s are 6v being driven by 2x 25R 18650s in series, and the light seems to be working just fine otherwise.
Is the LED (partly) dead? Does it just need a reflow?
It could be either since there are two pairs of series die’s that can be run 2s2p or 4s depending on the mcpcb. Regardless of that though LEDs often fail to a short so blown emitters don’t cause a break in the circuit allowing the remaining die’s to still light up. Try reflowing, it’s worth a shot.
Because there are two sets of dies, each set has 2 squares in series and the two sets are in parallel in the 6v configuration.
Either one set is dead, or it is not making proper contact to the PCB.