I was just wondering, is it possible to turn this 3 mode (H-L-Strobe) into a 1 mode direct drive light?
Looking at the driver my guess is desolder the negative wire and solder it to the outer ring. Will this effectively by-pass the driver and make it direct drive?
The torch is the MXDL SA-16 with an XR-E. The pill is hollow, but looks fairly substantial and has lots of good contact with the torch head/body. I know heat might be an issue, but not overly fussed as I want to try this more for fun than anything else.
Yep, that should do it. You could also just make a solder bridge from the outer ring over to the LED- pad, current won't flow through the driver circuitry as long as it has a lower resistance path to ground to take instead.
What setting would I use to “probe around”? I have a new DMM in the mail, and really have no clue how to use it. I’m going to make learning all the aspects of a DMM my new sub hobby.
Scaru. Haven’t seen much of you lately. If you are looking for a new project, “How to use a multi meter” in relation to all sorts of flashlight/battery applications could help a lot of members really understand what’s going on with their lights.
One tip is that you can use backlighting as an x-ray for most PCBs, depending on how much metal they have in em (doesn't work well on drivers like the SRK that have one side mostly covered by one big metal layer). Helps a lot to figure out where the traces go... check from both sides, some traces on the opposite side won't show up well. That can help you get an initial plan of attack for what to check first with the meter.
That’s not a FET, it’s a really cheap flashlight controller. I’ve seen it before. I think it even includes the ultra-awesome next-mode memory.
Ouchyfoot, to probe around with a DMM:
remove power from your target board
set meter to diode test/tone mode (usually has a picture of a diode and music or speaker icon
when the meter leads are shorted together, the meter will beep
This is helpful for finding where traces go on a PCB. It can be tricky on more complicated boards, but toning it out with a meter helps.
A complete pathway IS a short. No beep or reading of 'INF' or 'OL' on the ohms scale is an open circuit, or resistance so high the meter can't read it. Reading of 0.000-0.002 could be a solid trace on the PCB and any resistance over exactly zero is coming from the probes, their connection to the meter, or at the probes' contact to the thing you're measuring, OR, there could be a .001 ohm resistor hiding somewhere in the circuit...
If it's a board you don't have a schematic to refer to, you have to use both evidence gathered with the meter, and visual clues, to figure out the layout. If you can't shine a light from the opposite side to make traces visible, you can use oblique lighting shone across the board and sometimes the raised bits where the traces are will pop out so you can see them.
For something simple like the mod in the OP, just measuring from the LED+ pad to the BAT+ spring to make sure that's got continuity, and measuring from LED- to GND to make sure that's NOT got continuity, will give you enough info to say that the driver is regulating current on the negative side, and moving LED- to GND will bypass the driver completely, as desired.
Thanks comfychair. A good lesson. I’ll use that as soon as I get my DMM. I have a driver in my “oops” bin that seems to have gone one mode DD. I believe I upgraded the wires on that one. Now I know what to check for.
