Tech help needed plz: Intermittent connection [SF M3]

Hey y'all,

I have been experiencing connection issues with my SF M3 since I received it NEW and I'm hoping maybe somebody has a few ideas. At first I thought it was my LED Drop-in, so I switched back to MN10 lamp. I thought it was my 17500 setup, so I switched back to 3 primaries. Despite my efforts, I have found the error to present itself with every setup I could come up with, including the factory configuration.

I have used three different SF tailswitches, two factory twisties and a mcclicky'd one. I have used primaries and rechargeables with good charge.

[Notice] All setups will work when the tailcap is removed and a paper clip is used to complete the circuit. This includes when the bezel is removed and the lamp is allowed to "sit" in the lampwell. [Notice]

I can tighten down the twisty or click the clicky switch and 90% of the time, nothing will happen. If I shake or tap the light, sometimes I will get a flicker OR, rarely, it will come on for good. I have wiped down the threads numerous times. I have also tried stretching the spring. Maybe not enough?

Any thoughts or ideas?

Thanks in advance,
Chris

Sounded like a spring issue at first, but sounds like you have tried that fix already. I have some aftermarket dropins for my M6 with the center spring too soft and too short to make proper contact. Stretching helped a bit.

I'm not familiar with the M3, but there aren't many moving parts, so I would definately try to weed out the problem part.

The tailcaps proabably aren't the problem if the problem exists with all three. Clean the threads and contacts just in case.

Body tube doesn't do anything, but clean head threads and contact points anyway

Head also doesn't do much, except screw down and put pressure on the dropin, so make sure it is coming all the way down, check threads, and orings to make sure nothing is getting caught.

Last piece is the dropin's themselves. I am thinking the 17500's may have squashed the center spring a little bit. If you could stretch them out a little more, I believe they should be longer then the outer spring by 5mm or so. Is the LED dropin a malkoff? if so, do you need to shim it a bit to make contact?


Hope you figure something out, contact issues are not good at all

The drop in WAS a malkoff, but I sold it to return to factory incandescent configuration. The factory MN10 lamp gives me the same issue. Like I said, it lights up no problem with the tailcap off and using a paper clip using either cell setup. alas, i'll work on the spring some more.

thanks.

I had the same issue with my M3. Solved the problem by unwinding the negative contact spring a little to increase its diameter.

Thanks! I will try this.

[Edit] Tried all suggestions with either a. Temporary improvement or b. no improvement. [Edit]

It sounds like you have ruled out the usual suspects of batteries, bulbs, and tailswitch so it seems the problem would have to be at the other end.

Just to be clear, when following Not So Bright's suggestion did you unwind the outer spring on the MN10 enough so that it would fit around the battery? The outer spring on the MN10 is fairly soft and if the batteries are sitting too high in the tube, possibly due to a stretched tailcap spring, they will push the outer spring on the MN10 away from the lip where they make contact, breaking contact.

To eliminate as many variables as possible, do you have unaltered (as in unstretched) lamp assemblies and switches you could test with?

Hmmm. I had a similar issue with my 6p (with twisty/momentary tailcap) ages ago. I turned out to be that the spring in the tailcap wasn't sitting it its proper recess like it should. Using a screw driver I jammed it back in place.
As already stated its unlikely 3 tailcaps are all dodgy but check that spring is in nice and tight anyway.

So possibly an issue with the way your M3 body mates with tailcaps. Could it be out of spec?? (hate to say it, and personally doubt it)Do you have another M3 body to compare measurements with?
For example I am thinking the threaded tail part of your M3 may be different which stops the tailcaps from functioning correctly?
Maybe the body is shorter or longer?? so when putting on a tailcap you create a break in the circuit at the lamp end.

Just thinking out loud.
Hope you get this sorted, I have 2 M3s (just acquired one recently) one has a mcclicky the other is stock. My favorites!!

p.s Do you have any lanyard rings or aftermarket clips etc attached to the tail of you M3?:shrug:

Thanks for the help y'all. It appears that the spring of the MN10 lamp is causing the problems. I have tweaked it here and there and it seems to help considerably, but still not allowing full reliability. I will call surefire today and see if they can get me another lamp assembly out, since this one is new.

thanks again,
Chris

beach honda said:

Thanks for the help y'all. It appears that the spring of the MN10 lamp is causing the problems. I have tweaked it here and there and it seems to help considerably, but still not allowing full reliability. I will call surefire today and see if they can get me another lamp assembly out, since this one is new.

thanks again,
Chris

Click to expand...

How did you fare?

Interested in knowing what the problem was.

Rat6P said:

How did you fare?

Interested in knowing what the problem was.

Click to expand...

Rat,

I never was able to make the light 100% reliable so for now its been shelved. It's unfortunate, I really really like the M3, but for now I have no problem carrying my Z2/XML/SW01.