I recently picked up a MHP50 to try my hand at reflowing different LEDs onto MCPCBs to mod some of my current flashlights and to do new builds. Tonight I was doing a few multi-emitter MCPCBs and ran into serious troubles when doing a FFL5009R quad reflow:
Round 1 – Reflow and check with my SMD tester… three of the LEDs work, one of them only half-illuminates.
Round 2 – I must not have used enough solder paste on that LED. Okay, rework. Darn it, I chipped the phosphor layer and that LED won't light up at all now. Double darn it, now two more only half-illuminate!
Round 3… and 4 – Some more solder paste, some flux, and rework. Darn it again, the uncooperative LEDs won't work properly any more.
This is neither my first multi-emitter reflow nor first time working with Fireflies emitters (my favs are the FFL351A 3700k NW and FFL707MD 4200k), and the other two MCPCBs I did during this session went swimmingly: a SFT-40.2 2700k triple for D3AA and SFT-40 3000k quad for a S2+ mule (pics included to prove that at least something went right tonight).
I'm trying to figure out where I went wrong as this is the first reflow that has given me any sort of trouble. Are some types (or even batches) of LEDs just more sensitive or fragile than others?
by Zerufuru
