Trying to gather some parts and advice

Hello All,

I’m a relatively new member who has a nack for taking things apart and putting them back together.

I got into flashlights pretty heavily last september (whenever I signed up) and have been low-key collecting ever since.

I have a KD C8 that recently began malfunctioning and I’d like to modify it.

Issues:

I hate the tint - it’s almost purple!

The switch seems to intermittently misbehave. At times not allowing access to all modes.

I had the C8 apart and back together when I realized how simple it might be to modify (and when I found fasttech.com for the first time).

What I’d like to do is get a warmer emitter, keep the driver and poll and change the switch.

Fasttech’s website has me a bit confused and I was wondering if anyone could tell me if the following would work together…

Pillar

spring

emitter

driver

I am at a loss as to what tail switch to get.

I include the driver becuase the light currently pulls anywhere from 2.15 to 3.4A at the tail using my DMM. This is the only light I have that varies so greatly and I don’t know if the driver is working properly. I say that because the light is bright, but doesn’t seem that bright.

Additionally, the descriptiong of the pill asks for a 20mm star, but I”m pretty sure the light is using a 16mm star ATM. If I go 20mm, I’ll likely grab this led.

Any direction here would help.

Lastly, if someone could point me in the direction of a good thread on detaching the driver from the pillar, that would be great. I don’t see how it would be done easily. I’m assuming desolder the driver leads first, then find a way to pry it out?

I’d go with:
These springs: http://www.fasttech.com/products/1616/10001712/1347100
This driver: http://intl-outdoor.com/qlite-reva-71358-multiple-modes-circuit-board-304a-p-710.html
This emitter: http://intl-outdoor.com/noctigon-xm16-mcpcb-cree-xml2-t5-4c-led-p-751.html
:beer:

Relic 38,

Thank you for the suggestions. Any reason you recommend against the driver from fasttech?

The QLite has better mode options, and no audible PWM whine in med and low. Also, it has a very nice Moonlight mode if you choose to enable it.

Hi,

I don’t understand why you need a new “pillar” (aka “pill”) if you already have a working pill? Also others have posted that bare C8 pills don’t always fit every C8, so you’d be taking a chance if you get that FT pill, whereas you know for sure that the pill that’s already in your C8 fits.

Having said that, have you definitively determined that the switch is bad? Have you taken the tailcap off and just tried to short between an unanodized part of the body and the negative side of the battery?

Or, remove the pill, get some magnets and two jumpers with alligator clips, use them to hook the + side of the battery to the spring, and touch the jumper attached to the negative end of the battery to the pill, and see if it changes modes reliably when you tap the negative lead to the pill?

If it does change modes reliably, then it is probably a faulty (maybe sticky) switch.

If it doesn’t change modes reliably, then it’s probably the driver.

Jim

Jim, at the moment, the light is switching modes as it should. I’ll wait for the problem to reoccur and follow your testing methods.

As for the pill, I wasn’t sure how to remove the driver that is currently installed, but I butchered another light of mine tonight to find out how this all works and it’s easy enough. I think I’ll keep the stock pill.

Cheers for that. I do like a nice moonlight mode!

Was the emitter glued to the pill? Or not? Sounds like it wasn’t, which is lucky for you :). Note that one C8 may have it glued, whereas another may not… I’d guess that 2 C8s from the same manufacturer would be the same, but then you can’t really tell if it’s the same manufacturer, because a lot of them are re-branded.

As for troubleshooting, yes, it’s always good, but sometimes not easy, to try to do it step-by-step, eliminating as many variables first.

The emitter is glued to the pill. What would I do to remove it? Just pry?

It kind of depends what was used to glue them down, but the ideas that I’ve seen are:

- Freeze the pill, then heat it up, maybe a couple of times then pry (not too hard). This worked for me once.

- Use something like “BGA Epoxy remover” (Ebay). This worked for me once.

- Someone said you can take a needle nose, grab the star, and twist. I haven’t tried that yet.

Try freeze/thaw a few cycles first

Silicon based adhesives can sometimes be softened with isopropyl alchohol.

I twist them out (IF it is Fujik that’s holding it in).

  • Heat the star up a bit (OK a lot, use a soldering iron on a wire pad for about 20-30 seconds),
  • Take Need-nose pliers and insert them in the wire grooves of the star.
  • Press down very gently, enough to hold the pliers in place, no more. Too much downward pressure will scratch the pill surface.
  • twist the star with firm pressure, and try to control overshoot when the bond breaks. it will usually separate all at once. Apply constant pressure, increase very slowly if nothing happens for a bit. It should eventually break loose.

If it is any other type of adhesive, this will not work. However, most budget lights get the Fujik treatment at the factory.

I will try this evening and let you all know how it goes. I’m not worried about damaging the emitter, should I ensure the pill is unscathed?

If you scratch the pill, any raised metal might prevent the new star from making good contact. You will have to lap the pill to smooth it out again. Lapping is a good idea anyway, but a deep scratch can make it take a lot longer.

I ordered the driver and emitter mentioned above and the rest from fasttech. Should get started on this in a few weeks then…

I’ll do a search for lapping as I’m not familiar with this technique.

Search done - it’s a polishing compound, no?

You do not need a polishing compound, just some sandpaper and a flat surface. I start with 400 grit and proceed to flatten the star bottom. Once the entire surface has been scratched by the 400 grit, it’s flat. Now move up to 800, then 1500, then 2000 grit until you have a mirror-like finish. Some go to 2500 grit, I skip that.
For the pill, ti can be harder because they often have a raised edge. Use a piece of round bar stock (or something else with a flat end) and work a small piece of sandpaper over the pill surface. This can be time consuming and awkward.
Once both pieces are flat you use a small amount of thermal compound and squish them together pushing out as much compound as possible. Wire things up and you’re done! OK, reassemble the light and your done :wink:

The pill you listed is for emitters on 20mm pads, not 16mm as you have listed.

Choose this instead.

I was curious about this. I ended up ordering the emitter mentioned in an earlier post from I-O, I hope it works, though it is 16mm…

Sounds easy enough. Thanks!