Cheap Chinese Cree XM-L T6 modification

[chefslot]

So in regards to just having a strobe effect how would you accomplish this??

Regards

[0xdeadbeef]

You mean with the original design? IMHO this wouldn't be easily possible unless the strobe effect would be the default mode. Since all my modification did was to reduce the time the little SOT chip could remember the current mode before it reset to the default mode (which was high in this case).
I guess the best approach for permanent strobe would be to remove the SOT, put an oscillator circuit or even a small microcontroller (to create your few Hz PWM) in its place and connect it to the gate of the FET. Note: in the original circuit, the gate has to be pulled to GND, so you need some kind of open drain circuit or to configure a µC pin to "open drain" mode (which actually disables the highside of the push/pull output stage). Dunno if this would be worth it as the original design is somewhat crappy anyway. Probably it would make more sense to completely exchange the PCB (either buy one with a Tiny or design your own PCB with any small µC).
As a side note, in the meantime I replaced the PCB in most of my XM-L T6 flashlights. I think I have only one of these flashlights with botched PCB left.

[Rick Law]

You mean with the original design? IMHO this wouldn't be easily possible unless the strobe effect would be the default mode. Since all my modification did was to reduce the time the little SOT chip could remember the current mode before it reset to the default mode (which was high in this case).
I guess the best approach for permanent strobe would be to remove the SOT, put an oscillator circuit or even a small microcontroller (to create your few Hz PWM) in its place and connect it to the gate of the FET. Note: in the original circuit, the gate has to be pulled to GND, so you need some kind of open drain circuit or to configure a µC pin to "open drain" mode (which actually disables the highside of the push/pull output stage). Dunno if this would be worth it as the original design is somewhat crappy anyway. Probably it would make more sense to completely exchange the PCB (either buy one with a Tiny or design your own PCB with any small µC).
As a side note, in the meantime I replaced the PCB in most of my XM-L T6 flashlights. I think I have only one of these flashlights with botched PCB left.

Besides the issues 0xdeadbeef already mentioned, you need to check the clearance if any added parts are thicker than original.  I've mod eight T6/18650 based flash lights (from different sellers), some have extra clearance and some have none.  On about half of them, I had to add additional O-Rings just to get the extra clearance to fit the thicker-than-original (MCU based) driver into it.

So, before you start any modification, check how many dimes or pennies (or any different metal coins) you can put between the battery-minus and the spring and can still close the flashlight tube.  That will give you an idea on if additional clearance is there at all.  Otherwise, you have to factor in the cost/trouble of needing to get some O-Rings.

On one of them, there was no room to do anything at all!  I ended up just "killing the memory" by removing the capacitor so it always power on to HIGH instead of sometimes starting out with the annoying strobe mode.