Mod Warning - Resister Modding the TR-142B driver past 5.5 Amps will fry your XM-L(2)'s

Flashlight Modding and DIY Parts
1

Anyone try resister modding this driver for xml(2)? Been playing with one today and I have fried 1 xml2 and 3 xml's (all on copper and well heat sinked) before reaching 6 amps. All blew on startup in High mode. Just a flash and emitter's bond wires are blasted. The driver looks similar to the Manafont 3T6 but has a couple less components. FT's product page says its for the SST50. Given the Vf of the SST50, I figure this has to be a buck driver and should be fine with xml.

FT's site says its a TR-124B, but driver is labeled TR-142B.

2

Sounds just like what my S1100 driver did when I got the resistors too low. BANG, no warning, adding one more resistor went from 4.2A to direct drive straight from 3 cells.

What's the before and after resistor values?

3

Hey Comfy. I'm not sure. I was using a trim pot and was turning up a turn at a time. When the current got up a little over 5 1/2 amps, even just a quarter turn would zap the emitter.

4

I never got an explanation for why some drivers do that, not one that sounded like an actual reason. I think we'll just have to live with it.

My S1100 LED-killing adventure here: https://budgetlightforum.com/t/-/20635

5

Well, it helps to know that others do that. Sounds like this driver will only be used for MT-G2's for me. Thanks for dropping in to help Comfy.

I do recall you reporting your S1100 killing xml emitters with resistor mod now. Your S1100 still seems like the best MT-G2 build so far. You still running it these days with the MT-G2?

6

I had this theory that it was something called inrush current that killed the emitters.

But I havent got the equipment to measure it nor that exact driver. So I am just spitballing here as you say.