PK Knight Tailswitch

dchang0

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Sep 28, 2019
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Thanks to peter and Chauncey for responding in the other, main thread about the Knight/Paladin.

My Paladin seems to have some small metal piece floating around inside the tailcap.

Looking at the diagram from PK that peter posted up AND combined with the photo badtziscool posted, it does look like the safest way to remove the tailcap is to simply screw it off and hope that the retaining ring pops inward.

I figure what I need to do is come up with a way to really torque on the tailcap and body without damaging either's finish. Maybe a pair of tiny strap wrenches wrapped tightly around inner tube scraps...

UPDATE: Just noticed that Prometheus has tiny resin wrenches for flashlights, but they seem to be limited to one specific size. So far, the rubber strap wrenches I am finding don't go down to less than 1.5in in diameter.
 
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AVService

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Dec 30, 2011
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Not too sure if this is pertinent here or not but when I had the same kind of issue with a Ti Mini MKII the problem ended up being an almost microscopic sliver of metal somehow loose inside the threads where they make and break contact thus switching the light off and on or in my case on and on which is what yours seems to be doing as well?

I knew that there had to something like this going on but again the sliver was so small that I just couldn't see it at all almost.
I finally took a small pick tool and slid around the threads lightly and it peeked out a little and I was able to figure out what was happening and since removing the tiny metal shard the light is just fine again for me!

I only half understand the cutaway view that is posted but I bet if you can get in there it can be fixed as well.

Thanks to peter and Chauncey for responding in the other, main thread about the Knight/Paladin.

My Paladin seems to have some small metal piece floating around inside the tailcap.

Looking at the diagram from PK that peter posted up AND combined with the photo badtziscool posted, it does look like the safest way to remove the tailcap is to simply screw it off and hope that the retaining ring pops inward.

I figure what I need to do is come up with a way to really torque on the tailcap and body without damaging either's finish. Maybe a pair of tiny strap wrenches wrapped tightly around inner tube scraps...
 

dchang0

Newly Enlightened
Joined
Sep 28, 2019
Messages
15
Not too sure if this is pertinent here or not but when I had the same kind of issue with a Ti Mini MKII the problem ended up being an almost microscopic sliver of metal somehow loose inside the threads where they make and break contact thus switching the light off and on or in my case on and on which is what yours seems to be doing as well?

It could be a sliver of metal, but I suspect that it's bigger than that because there are times when it actually blocks me from pressing the tailcap down. In these rare moments, the tailcap feels solid, like it's locked out, so I figure the broken piece is about 1mm in thickness.

I'm wondering if it's possible to get to the metal piece through the center of the PCB to which the battery spring is attached (the PCB is green in the diagram peter got from PK).

If the battery spring simply pulls out (not soldered) of the PCB, I might be able to fish around inside the contact mechanism with a dental pick. But I'm wary of doing this because if the battery spring can't be put back into the PCB, I'm screwed. Maybe I can fish around without having to remove the battery spring...

UPDATE:

Can't get the dental pick in there due to the cramped quarters, but perhaps a paper clip bent at a sharp right angle will work.

UPDATE 2:

Even a paper clip is too thick. It won't fit between the coils of the battery spring. Well, I can get a straight paper clip through just one spot, but not a bent paper clip.

Probably doesn't matter, as the loose piece of metal is more likely to be on the other side of the contact plate.
 
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Got Lumens?

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Even if You were able to get a pick in there, just one pick would not be enough points to slip the tailcap past the slot stop of the steel compression ring.
I've checked the different blow ups. It looks like in order for it to work, the o-ring would need to be removed(destroyed) first in order to ensure the thin metal goes on top of, and not under the steel compression ring. A fixture of sorts that compresses ~>= four thin(~.008"?) 3/16 wide L shaped inserts might be able to be fabricated to work. ???

There may be a thermal possibility. It might be possible to heat the entire light (Dry, in a bag)boiling it and then use freeze spray(canned air inverted) on just the body. If a ~.0075 difference can be achieved, You maybe able to get the Steel ring to compress and slide past the ridge trying to remove the tailcap. Aluminum thermal expansion is greater than steel. You could try the reverse by freezing the entire light, then heating just the tailcap externally, but that may be risking some damage to the tailcap's PCB components. It all depends if the steel ring is round, and not a square specialized shape. If You try external heat, make sure it's a heat gun that won't overheat the anodizing and components on the PCB. Having PK's input on not knowing how, leaves some doubt on my suggestions. I hope You get it fixed soon, take care, GL.
 

badtziscool

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There’s electronics in the tailcap? I thought it was all a mechanical switch. I’ve thought about using feeler gauges to see if I can wedge it up in there with the hope that it will allow the spring to slip off the shelf. Haven’t tried that though. Mine still works. Just not very smoothly so I’m still not at the stage where I want to do something that will damage the light.
 

dchang0

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Sep 28, 2019
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@Got_Lumens?

Oh, I'm not trying to use the dental pick to remove the tailcap. Just hoping I could fish out the broken piece of metal floating around inside. But from my testing with a bent paperclip, it seems that the broken piece of metal is on the other side of the flat contact and thus cannot be fished out.

Thanks for your other suggestions, though. Those may work, though like badtziscool said, "I’m still not at the stage where I want to do something that will damage the light."

@badtziscool:

No, there are no electronics in the tailcap. Sorry if I worded it poorly. There appears to be a simple metal contact plate that the tailcap touches when pressed. The battery spring is attached to the metal contact plate.
 
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