How to: Modding the Maxtoch DX21

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TexasToasted
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How to: Modding the Maxtoch DX21

Amanda at Maxtoch was kind enough to send me a DX21 with the bezels not glued. Unfortunately, the electronics were completely smothered in glue. The way the light is assembled, the electronics have to be glued in. The glue is what holds the switch/driver board in alignment with the mechanical switch plunger and holds the battery positive terminal plate so it does not fall out- they did not use a screw-in retaining ring to hold the guts in the head, just lots and lots of glue.

When I saw how this light was assembled, I figured I would have to destroy the electronics to get them out of the head and rebuild it with a new driver and switch assembly. But after I got it apart, I think I may be able to soup up the factory driver and reinstall it. Maybe.

Being a bit of a procrastinator and knowing that I may not ever finish this project, I figured I’d share what I learned so far in case anyone wants to mod their own DX21.
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Here is the view from the front. Stainless steel bezels, 4mm thick glass lenses, o-rings, and screw-in reflectors. After you remove the bezels, o-rings, and glass, there is just enough of the reflectors sticking up to gently unscrew them with needle nose pliers. Mine were not tight, so were pretty easy to unscrew. I just went really slow so as not to slip and scratch anything.
The LEDs were installed on 20mm aluminum MCPCBs and were glued down with the standard silicone type goop. I used a beefy pair of needle nose pliers to twist the MCPCBs loose. It was not easy. I did tear the wires off, but didn’t care since I am not re-using them.
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I’m jumping ahead a bit to show the driver board and the battery positive contact board. That white goo you see on the round contact board is some of the glue that held that board in the light. There was a lot of that glue. This picture is after I scraped most of off.
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Here is the other side of the contact board and the driver. Before you take the board out, you can see the glue all around the edge of it. You can see it in this picture.
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To get out the contact board and gain access to the driver, I turned the head so the contact board was facing up and poured some of this adhesive remover on top the contact board and let it soak for a while. I had to cover the opening with a large Snapple bottle cap to stop the adhesive remover from evaporating so fast. I don’t know what’s in this stuff, but it really works. It turned the hard glue into a gooey mess.
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But I still couldn’t get the contact board out. There was too much glue down inside the head holding it in place. I poked a thin, pointy awl into one of the holes that had previously held the LED wires and I pounded the board out from the front. I did poke a dimple into the board from the point of the awl and I rubbed a couple of components off the driver, but it might be fixable.
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And, here is the driver! Your driver won’t look like this though. It will be smothered in the white glue and the same gray silicone adhesive goop that’s used to glue down the MCPCBs. This is what it looks like after you dig out all that glue and spend a couple hours gently scraping it off the board and out of the light.
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This is a close-up of the switch plunger mechanism. You see a steel shaft with an e-clip protruding out of a clear plastic housing. That’s the waterproof switch assembly. BE ADVISED- that clear plastic you see there will be dissolved by the adhesive remover I showed earlier! As soon as I realized the adhesive remover was eating the switch assembly, I wiped it dry and let a fan blow on it to evaporate the adhesive remover. I think I got to it in time, it seems to still work OK.
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This is the front of the driver after scraping off all the goop. The damaged resistor (I think) in the bottom right corner, next to the -OUT LED connection was caused by my awl.
The LEDs are wired in parallel to -OUT and +OUT. You can’t read the +OUT in the lower left corner because it still has a little of the gray goop covering it.
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The back of the driver. Notice that a 7135 regulator is missing. I wiped it off the board when I was poking the awl through from the front. I didn’t care since I was planning to replace the driver, but now I’m thinking I may be able to replace this 7135 and just piggy back all the 7135s to boost the output to where it should be.
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A few details- (I use a cheap, plastic Harbor Freight digital caliper, so my measurements are not guaranteed to be precise.)
The contact board is 29mm diameter, 1.5mm thick.
Reflectors are 26.4mm diameter, 18.3mm tall, with a 6.8mm opening.
Driver board 24mm wide, 14mm deep, 1.4mm thick.
Lens 29.3mm diameter, 4mm thick.
The driver uses 8×380mA 7138 drivers, so it can supply 3.04A to the LEDs, which are wired in parallel meaning that each LED is seeing about 1.5A. We can do better than that :bigsmile:

Edited by: TexasToasted on 05/18/2014 - 21:07
musicmagic
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can’t help but notice the board name. Shadow SL2. as in the flashlight brand?

it looks like you can fit 2 7135s on the front of the board.

If you can’t blind them with your brilliance, baffle them with your bullcrap.

The real currency in the world is not money, it’s trust.

TexasToasted
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The round contact board also has Shadow written on it. Maxtoch painted over it, but I can still read it.

TexasToasted
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Replaced the missing 7135 and everything is working properly. Even 3 little battery monitoring LEDs are still working.
Now I just need to order a couple of neutral white XM-L2 LEDs and tack on a few more 7135s.

texas shooter
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I’ve been a big fan of the twin led style. Just adding the missing 7380’s would be a nice start. This also might be a good host to work with. http://www.fasttech.com/products/1601/10007668/1663800-lzz-01-2-cree-xm-...

musicmagic
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I was just going to pm about the lzz-01. have you ripped it apart to look at the internals?

If you can’t blind them with your brilliance, baffle them with your bullcrap.

The real currency in the world is not money, it’s trust.

TexasToasted
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Eventually I’ll do a full review on that one, but I have too many projects going on. I did post a review at Fasttech.

Good:

  • Very easy to mod- no glue.
  • User interface is good. It has disco modes, but if you cycle the tailswitch, the UI resets to the start level (high), so you don’t have to cycle through disco.
  • No visible PWM on any level.

Bad:

  • Sharp, fine, rough cut threads.
  • Weak- not very bright.


The driver pops right out. I added an R330 (0.33 Ohms) from Fasttech to the stack of sense resistors to increase the current. It worked, but needs more. I’ll tweak it some more later.

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Uses standard 20mm LED MCPCB.

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Cheap, thin plastic lens, & thick LED spacer. Everything comes apart real easy.

texas shooter
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I’ve always wanted to mod the DX21 or the Shadow TC-750X to a triple XP-G2 on one side and an XM-L2 on the other. Put high on 2-3 amps each side, perfect flood with throw. But I could never tear one down enough to pull it off, just too much glue. This no glue version might work all the heads seem to have been made by one manufacturer. Both the TC-750 and the DX21 use a P60 size reflector, even the Solarforce/Surefire bezels fit the early TC-750’s. Texas Toasted your modding skills look a bit better than mine. Think about trying this type of rebuild.

musicmagic
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Thank you for the pics.

If you can’t blind them with your brilliance, baffle them with your bullcrap.

The real currency in the world is not money, it’s trust.