Flickering UF-2100

Tested it with a DMM sans tailcap and it still flickered on high, so I guess its the driver then?

Kinda looking forward to putting in a 2.8a driver and improving the heatsink…

Is the pill making good contact with the body? Lose connections?

Also depends on whether your DMM was getting good ground. Closely examine the solder the driver and LED. There should be something visible in wiring or soldering if it is the assembled pill. I think some of those problems have been reported, but it is less common.

I’d probably change the switch anyway - I’ve saved the oem to perhaps try it in another light some time, or in case I find an insert clicky to replace just that part of it.