I’ve just done a straight swap of my XP-G R5(Trustfire R5-A3) for an XM-L2 and found that it wasn’t as bright as expected and the five modes no longer work. The brightness is probably due to it being stuck on mid brightness which is what it was set to prior to the swap.
I then put the XP-G back in and the modes, again, do not not work and it seems to be stuck on mid brightness.
Why would this happen? Any ideas?
Tom.
How did you swap the led?
Did you verify that led isn’t connected directly to ground? No insulation on the wire was melted through? Although the led would probably be very bright if the driver was bypassed. Did you solder at the driver or at the led star?
Hmmm. I’ve found those drivers that take AA or 14500 can act pretty flakey sometimes.
What are you running it on.
THIS is the LED I bought.
I simply desoldered the exposed wires and removed the XP-G and dropped in the XM-L2 and resoldered.
The condition of everything seems fine.
I’m using Trustfire and EVVA 14500 cells.
Tom.
By chance, did you leave the battery in while soldering?
No, completely stripped down.
Tom.
Well this is very strange! I just gave the torch to my daughter and after she used it I tried the modes again. Low and behold they are all working again; Hi, Mid, Lo, Strobe and SOS.
The only thing that has happened is that she had it on for a minute or two.
Tom.
So, it’s either a flakey driver, or a flakey switch.
you might have had a tiny little whisker of solder making a short, and melted it.
Look really carefully at where the positive wire curves over the edge of the LED board and down into the head of the flashlight.
If a tiny bit of solder followed the insulation over the edge of the board and grounded that way, it might have melted away or broken loose with handling.
Yes, but if had been shorted to ground it would have gone into direct drive. I don’t think it would be confused for mid mode.
A faulty switch could be the culprit. If it had mode memory, and the switch wasn’t working right it would remain at the same mode. I think I’d take a look at that. At least make sure it’s all tightened down. If this happens again, I’d look there first.
Actually, if it happens again, and you can change modes by grounding the battery to the body with the tail cap off, then you know it’s the switch.
Happens all the time. I hand my daughter something working and she breaks it. Hand her something broken and….who knows!
Always check retainers for tightness on both ends. Bad contact here could cause both odd operation and an inability to pass full current along.
Phil
I swapped cells the other day and now I’ve only got full beam.
Anyway, I’ve ordered some new driver boards, THIS and THIS.
Tom.
Why the 17mm drivers? Unless there are different versions of this light, the Trustfire R5-A3 uses a 14mm driver. I did the strobe delete & XML mod to mine about 5 years ago. The driver lasted less than a year before going up in smoke, so I turned it into a single mode direct driver (no driver). This light probably has the best heat sinking of any 14500 light made. 
If you had worked on the driver I would suspect the flux (“need-to-clean” type) turns conductive when hot and shorts the memory retaining capacitor. Or if you had pencil mode reset mod (also same as above, swap flux with carbon filler).
But since you did a simple emitter swap, maybe the driver just couldn’t take the current increase.