Yes, I realize I'm pulling a Lazarus here on an old thread, but I too have just come up against this issue and was hoping someone could shed a bit of light on the actions mentioned in this thread.
Thus far, I have what I call the second gen M3, the one that has the contoured z46 bezel, not the "classic?" version that is more entirely cylindrical. Like new condition.
I have a new, LM EO-M3 incand. lamp
Two new, and freshly charged KeepPower 17500 cells from a reputable retailer.
What I've found:
Lamp energizes fine and functions properly with three primary, brand cells: SureFire, Panasonic and Streamlight.
The lamp will not energize when everything is "buttoned up", that is, factory z44 tailcap rotated all the way up to constant on, also, at no point will the lamp energize at any point while rotating on the tailcap onto the body.
The lamp WILL energize when the cells are shorted to the body.
I retrieved a Malkoff Tricap and found it would not work as with the factory cap.
I did find that using the Malkoff STANDARD cap, that the lamp will energize when the cap is rotated to appx 3/16" from all the way up, and once, it "clicked on" when fully rotated on but only once or twice.
The excellent customer service at Lumens Factory was at a loss as to a remedy, and I feel that's quite reasonable, I believe they adhere to known standards that may often be circumvented elsewhere.
Please pardon my ignorance but what is a "LA spring" and which spring referred to in this thread is to be "stretched"? Moreso, is there any known diagram or YTube vid showing this procedure?
Grateful for any assistance.
-Dave