A Leslie Wong Blog

After I put in a 3 mode 1.4 A driver in my Malkoff Devices M61 drop-in, I wasn’t too happy with the yellow/green tint of the Cree XP-G LED. I found a cooler tint XP-G and applied some Arctic Silver 5 Thermal Compound to the back of the LED board and used some Arctic Alumina Thermal Adhesive to hold the assembly in place.

Before I reassembled the drop-in, I wiped some hazing off the reflector with some chrome polish and inadvertently removed some of the reflective finish. I needed a new reflector.

I searched for reflectors for the Cree XP-G and found positive comments about Don McLeish’s McR-20 Seoul reflector. I ordered one from the Sandwich Shoppe and it was delivered in 2 days.

There is a recess around the top of the M61 heat sink that the top of the stock reflector sits in – that’s the flat part of the reflector. I put a GITD (Glow In The Dark) O-ring in the recess and it held the McR-20S reflector perfectly. The new LED is mounted on a thinner circuit board than the Malkoff board, which in this case helps with the reflector placement. The bottom of the reflector (with a thin insulator) rests on the LED board. The other end of the reflector is flush with the end of the heat sink.

The beam is very nice. Compared to a M60 or M30, there is less of a hot spot and more spill. The stock M61, IIRC, didn’t have as much of a hot spot compared to the McR-20S.

So far in this mod, I have destroyed the Malkoff M61 driver board and damaged the reflector. But now I’m happy with a drop-in that has a great heat sink, a great beam and three modes. It’s now in my current favorite flashlight, the Surefire C2.

I received my Malkoff Devices M61 drop-in last week. The drop-in uses a Cree XP-G LED and it’s designed to replace the lamp assembly in Surefire 6P style flashlights. Malkoff Devices says, “the output is approximately 260 measured out the front lumens.” It is a single mode drop-in.

I bought the M61 with the intention of modding it with the Shiningbeam three-mode regulated circuit board (SKU 1218). The Cree XP-G datasheet (PDF) had recently noted an “increase of maximum forward current to 1500 mA for XLamp XP-G Cool White is retroactive and applies to all XLamp XP-G Cool White LEDs produced by Cree. The increase is the result of more extensive qualification testing that was performed after the initial product launch.” The Shiningbeam board output current is 60 mA on low, 440 mA on medium and 1.4 A on high.

First, I removed the potting and contact spring. In the process, I destroyed the Malkoff driver board. I used a Dremel to reduce the diameter of the Shiningbeam board so it would fit inside the drop-in.

The Shiningbeam board works as advertised – I measured 1.4 A on high, 450 mA on medium and 65 mA on low. I’m not enamored with the yellow-green tint of the LED; maybe I’ll replace it down the line.

I have also used the Shiningbeam board in a DealExtreme XP-G R5 drop-in (SKU 32954). The result, compared to the Malkoff, is a little more throw and a lot less spill. The tint of the DealExtreme LED is also cooler – more blue.

After disassembling the M61, it’s clear that this is a most robust, superbly constructed drop-in. I can see why a professional would be able to rely on this drop-in in a life or death situation. But flashlights for me are a hobby, which is why I wanted to mod this drop-in to have (a more useful for me) three modes.

You’d think a 3D cell Maglite would be pretty bright. It’s over 12.5″ (310 mm) long and weighs over 30 oz (850 g) with batteries. With the standard Krypton bulb, the 3D Maglite puts out about 76 lumens. A flashaholic wants 76 lumens from a keychain light.

The Maglite may be behind in bleeding edge illumination technology, but flashlight modders like them because it’s a great platform to build upon. One of my first mods was the Roar of the Pelican – a 2D Maglite running on 6AA batteries and a high wattage bulb. It puts out about 600 lumens.

There are many LED Maglite mods that will put out a lot of light. Multi-chip LEDs – the Cree XLamp MC-E, Seoul Semiconductor Z-Power P7 and the Luminus SST-50 and SST-90 PhlatLight LEDs are popular because of their high outputs. You just need a heatsink for the LED, a driver and suitable batteries in a combination that won’t burn up any of the components. A lot of people have figured this out for you. Google.

I decided to do the easiest high performance 3D cell Maglite upgrade: Malkoff Devices’ Maglite drop-in with the Cree XP-G LED. It’s not as bright as a multi-chip LED mod, but the Malkoff drop-in uses regular alkaline D cell batteries and it has a six hour runtime at full output. The only problem with the Malkoff drop-in is that it’s difficult to buy because it’s so popular. Once they are in stock, they sell out quickly. Malkoff Devices back-in-stock email notification system will alert you when they’re available, but even then you have to be fast.

Installation is simple: remove the existing bulb, push the drop-in down as far as it will go inside the flashlight and tighten the screw (which wedges the drop-in’s heat sink against the flashlight body). The bottom part of the reflector needs to be cut off to accommodate the drop-in. This is a simple cut with a razor saw. If that is too much for you, Malkoff Devices sells a pre-cut Maglite reflector for 7$.

Malkoff Devices description: “This dropin produces a real 260 (measured out the front) lumens in a 2D or 3D light with alkaline batteries. The Drop-In module is constructed of CNC machined structural aircraft aluminum and has a regulated driver. Full heatsinking of the driver and LED insure that the module can, and will, run at maximum output for extended periods. It will easily illuminate objects at a distance of 1000+ feet and will light a 2 inch red reflector at a distance of more than 1/4 mile. If you shine someone with this at night, within a 100 ft radius, they should see spots for a good 8-10 seconds.”

The current high lumen output LEDs use multiple chips on a single die. The Seoul Semiconductor Z-Power LED P7 and the Cree XLamp® MC-E LED are two examples that are in popular use by flashlight modders.

I recently bought a DealExtreme Cree MC-E LED 3-Mode Drop-in Module ($18.30 USD) for my Surefire 6P flashlight (the 6P body is bored to work with a single 18650 battery).

The DealExtreme P60 size drop-in works with 2.7V~4.2V – a single Li-Ion 18650 battery, single RCR123A battery or CR123A battery. There is also a not too low level mode and annoying strobe mode. In the Surefire 6P host (about 5.2″ long – 13.2 cm), the DealExtreme Cree MC-E drop-in is an extremely bright flashlight in a small package. There is an extensive list of similar sized flashlights that use P60 size drop-ins in this Candlepowerforums.com thread.

DealExtreme seems optimistic in their description of the MC-E drop-in brightness as 410 lumens. It has more flood and less of a hot spot than the Malkoff M30. For comparison, my Malkoff Devices M30 output is rated at a realistic 235 lumens. My SSC P7 mod, inspired by jirik_cz, gives me the feeling that I am seeing everything. If not for the $125 USD cost, I would be all over the Malkoff M60 MC-E (NLA).

In my flickr set below, there are beamshots comparing the Cree MC-E, Cree XR-E and SSC P7. I centered the beam of each light on the scrawny tree against the fence.

When I bought my first Surefire 6P flashlight, I found that the Malkoff M60 (now replaced by the M61) was one of the best P60 LED drop-ins.

I like the beam profile produced by the optic in the Malkoff M60, a hot spot with useful spill. The disadvantage of the Malkoff M60 – for me – is its single mode. I do not need 100% brightness all the time – lower levels of light are sometimes more useful.

One of my favorite flashlight mods is using the DealExtreme 16-Mode 3W 3.7V 7135 Circuit Board for Cree and SSC Emitters (SKU 7612). I like this circuit board because one of the groups has only low-mid-high, with no strobe. I’ve modded my Lumapower D-Mini, an Ultrafire C2 and a few P60 drop-ins with this board.

The modes are in three groups:

1. Low (10%) – Mid (35%) – High (100%) – Strobe – SOS
2. Low (10%) – Mid (35%) – High (100%)
3. Low (10%) – Mid (35%) – High (100%) – Special Police Type Strobe – Slow Strobe (3Hz) – Super Slow Strobe (1Hz) – SOS

I recently bought a Surefire 6P flashlight body that was bored to accept a larger diameter 18650 battery. I thought the DX 7612 would be a good mod for a Malkoff M60. The main problem was getting up the nerve to try to mod the Malkoff M60 because of the possibly destroying a $55 drop-in, but I decided to try it.

The sealing material used around the circuit board and LED in the M60 is called potting. The rear of the drop-in is sealed with this material. I thought it would be a hard material but I found the it was actually soft and rubbery. I used a jeweler’s screwdriver as a chisel to start removing it. As I got close to the circuit board, I used a little lacquer thinner to soften the black sealing material. When I removed all the potting from the top of the board, I used some more lacquer thinner to soften the material in the gaps in the side. After removing the solder, I was able to pry up the circuit board and remove it.

The diameter of the DX 7612 board is about 17mm. The Malkoff had about 16.5mm diameter space for the board, so I used a Dremel sanding band to reduce the diameter of the 7612.

As I disassembled the Malkoff, the robust design was easy to see. When I desoldered the Malkoff circuit board from the housing, I could tell from the way it retained the heat (because of its mass), how well it would work as a heat sink inside the flashlight body.

With the DX 7612 on high and an 18650 battery, the modded Malkoff output looks pretty much the same as the stock Malkoff M60 on high with two RCR123s. I haven’t taken any measurements, but the specs for the 7612 says it puts out 1000ma @ 3.7v, and since I didn’t move the LED or the optic, it seems like my modded Malkoff M60 is just like the stock one but with different levels.

I bought a Surefire 6P to house my Malkoff Devices M60 drop-in. You have to be kind of a flashaholic to understand that sentence.

Surefire describes the 6P as a “Compact (pocket sized), high-intensity incandescent flashlight for tactical, self-defense, and general use. (It) produces a smooth, brilliant, pre-focused tactical-level beam with three times the light of a big two-D-cell flashlight.”

The 6P’s stock lamp assembly is a P60 incandescent lamp. You can stop right there and you have a great flashlight that puts out 65 lumens.

The Malkoff Devices M60 drop-in (now replaced by the M61 with a Cree XP-G) uses a Cree XLamp XR-E LED (Q5 bin) as a replacement for the incandescent lamp. In addition to being more rugged, it puts out 235+ lumens. Gene Malkoff, the creator of the M60 says, “It will easily illuminate objects at 350+ feet and will blind opponents within a 100 foot radius.” That’s what we want.

Naturally, when I get something new, I take it apart and think about how to mod it. My new Surefire’s switch seemed like a good candidate.

The Surefire Z41 tailcap is standard on the 6P. It has a momentary option by pushing the tailcap switch. Rotating the tailcap will turn on the light for constant operation.

Most of my flashlights use a forward clicky switch. A slight press of the switch (before it clicks), will momentarily turn on the light and a full press (when the switch clicks), will latch it on. I’ve put the McClicky switch in seven or eight of my flashlights and thought it would work well in the Surefire 6P. I could have bought a Surefire Z59 Click-on Tailcap Switch or the Oveready McClicky Kit for USD $22, but it’s more satisfying making my own.

I yanked out the insides of the existing switch and unscrewed the retaining ring. Sometimes the retaining ring is glued. I’ve put the tailcap in a ziplock bag and boiled it hot water for five minutes and the glue will release.

Since I only had a plastic retaining ring to hold in the new switch, I soldered a piece of brass to the McClicky switch so that it contacts the inside of the switch housing. I put a dab of solder on the contact on the other side so the retaining ring would seat the switch flat inside the tailcap.

If you have an aluminum or brass retaining ring, there is no need to solder a tab – just screw it in. You must be careful about the inner part of the retaining ring contacting the positive connection on the raised plastic below the contact spring – it will short out the switch and be “on” all the time. A piece of shrink tubing or electrical tape wrapped around it will prevent a short.

Using that piece of brass also meant I had to remove the anodizing from the inside of the housing so the brass tab makes electrical contact with the side of the tailcap. With one mod that I did, I lost the lock out function, which “prevents accidental activation of light during tactical engagements, transportation, or storage,” according to Surefire. On another mod, the lock out still worked. In my case, I’m very unlikely to have a tactical engagement, so I can remove the batteries for transportation and storage.

To bottom it off, I replaced the black rubber push button cover with a Glow-in-the-Dark Silicone Tailcap…maybe a not too tactical feature.