I picked up a flashlight from Twosun, a brand more known for their knives. The titanium and copper machining is pretty nice, but the driver and emitter are disappointing. I’m looking at changing out the driver and LED, but I’ve run into an unexpected snag: I can’t even figure out what kind of switch is being used. So I don’t know if I should be looking for a driver set up for a clicky or an eswitch.
The switch is located in the tailcap, and it feels like an eswitch. However, the light doesn’t have concentric tubes like on a Wurkkos TS10 to deliver the power and switch signal separately to the head. Another tidbit is that the light briefly flashes when I put it back together, similar to an HDS Rotary.
I’m not familiar with that light. Do you have a multimeter to do some continuity tests? Remove the head and see how continuity between the tail spring/contact and the body theads is afftected when you press, hold, etc. the switch.
Welcome to BLF! That’s an unusual light, more pics would be appreciated! The copper and design of the switch button give me Duracell vibes.
Is it straightforward to open the tailcap? Usually there’s a retaining ring which unscrews and the switch assembly should (might) just drop out and allow you to get a better look at it. Be aware that some lights use reverse threaded retaining rings, and some manufacturers like to use thread lock, so if it’s not immediately easy, then don’t force it.
What does the inside of the head look like, where the positive contact for the cell is.
I believe there are ways to make e -switches work without a signal tube but this requires capacitors in the tail and I’m not sure I’ve seen it used on commercial lights.
That’s a good idea with the multimeter, I’ll try that when I get home! It looks like the tail switch might come out with needle nose pliers, maybe there are some clues in there…
Yep, remove that retaining ring and the switch assembly will pop out. That’s the most direct way to see what’s going on. Sometimes the rings are left hand threaded so don’t muscle it too hard before trying the other direction.
Some tailcap switches are the driver. They’re in series, so with power off, they can suck up a trickle of current actually through the load to charge up a small onboard cap, which is then enough to crowbar a FET across it to turn on the load (LED). When the board senses its voltage is dropping, it takes another hit to charge up.
Basically, they have a maximum of 99% duty-cycle or so, being “off” 1% of the time to charge up the cap.
Ok, so I couldn’t get any continuity touching the contacts on the body that the head connects to (with the tailcap and battery installed). I tried the tail and head by themselves, and the head contacts gave a resistance about 100 ohms. The tail contacts showed a resistance of about 600 ohms and didn’t change when I pressed the button.
I’m no expert on this, so I have no idea how to interpret this. The head certainly has a driver, but it seems there’s something else going on in the tail. Its there a test I can run to determine if the tail has a driver that allows a clicky driver to work in the head?
try diode test both ways, if there’s an actual driver in the tailcap and a charger near the head, i’d expect an anti-parallel diode to let charging current through
