The Aleph Light engine consists of a threaded and anodized Aluminium heat sink (E-Screw),

a nickel plated brass can for hosting the converter board (ES-Can), the converter board itself,

lead wires, an emitter PCB and a Luxeon LED.

A ground or (-) lead needs to be soldered to the ES-Can prior to assembly. This lead can be

soldered to a groove cut or filed into either the forward or rear lip opf the can or a small hole

drilled into the side of the can. The builders tools as well as nature of converter board will dictate

the best placement of the ground wire. Below, ES-Can's are shown with two possible ground wire

locations, prior to soldering and after being "cleaned up":

It is very important to plan the wire leads to the LED as well as the ground wire and test with dry

fitting prior to any bonding or potting. There is a milled channel in the bottom of the E-Screw

which can be oriented, if needed for allowing clearance of the ground wire if it is attached at

E-Screw end of the can. In the image below, if you look carfully, you can see that the converter

board will be glued into the ES-Can in such an orientation that the soldered ground wire will be

located below and in line with the milled slot in the bottom of the E-Screw. For reference when

looking from above, the milled slot is in the same radial angle as the milled "drive" notches on

the top of the E-Screw. In the image below, a black mark on the lip of the ES-Can is to indicate

where the red + LED lead will be oriented when the converter is glued down onto the shoulder

within the ES-Can. A crazy glue is good for this bond.

The converter is glued down into the ES-Can and after the adhesive sets, the ground wire is

soldered to the converter and any open vias are filled with solder (if one remembers) so that

epoxy won't weep out of them during potting. In the picture below, the ground wire has been

soldered to the converter. The tail will be trimed and a solder ball will be added to the anode

contact. There is one open via that might have gotten filled as well.

The converter in can is ready for assembly but the LED needs to be bonded to the E-Screw first;

at least this is my prefference.


To install the LED, the LED emitter PCB is first placed in the front bore of the E-Screw and the

lead holes are lined up with the holes through the E-Screw. The E-Screw is then screwed up into

an Aleph head. At this point, I use Arctic Silver epoxy and place a small drop and spread it on the

LED mating surface of the E-Screw.

The LED is then placed down onto the E-Screw:

The LED is roughly centered by eye with care given to the emitter leads ligning up with the

solder pads on the emitter PCB. A reflector is then dropped into the head and some type of non

scratching probe or tool is used to center the LED as well as force it down to press out excess

epoxy. I use a clear acrylic rod that I have machined a concave recess in the end of. This aids in

fitting over the LED lens and makes moving the LED easier. The tube section of a plastic ball

point pen can also be used.

Once the LED is bonded to the E-Screw, it can be removed from the head and at this point, I

pre-solder the LED leads down to the emitter PCB. I also pre tin the lead wires that will be

soldered here to these points. I have found that if the LED leads are trimed to a length of 3/4"

above the surface of the converter board, they are a good length for final attachment to the

emitter PCB. I have a small, flat blade screwdriver that I have notched to act like a "snake

catcher" in managing the LED lead wires and forcing them down in contact with the emitter PCB,

at which point I reflow the solder on the PCB as well as the tinned lead wire and effect a soldered

connection. Now that the E-Screw is sporting the LED and the ES-Can is host to a ground

connected converter, it is time to pot and join the two. I use Arctic Alumina epoxy for this

process. I fill the can to a level that would be even with the sluc on the bottom of the E-Screw that

drops into the ES-Can's interior. I also fill the milled slot on the bottom of the E-Screw with

epoxy. This filled slot, when cured, provides a raised "shear section" when bonded with the

epoxy in the can and this will allow for torque on the can in installation or removal of the Light

Engine from the head.

If you have gauged the proper amount of epoxy, when the two components are joined and

pressed together, some epoxy will come out of the lead wire holes. Excess can be removed with a

toothpick as the two parts are joined and pressed together. Another method of potting is to bond

the two components ahead of time and a hole can be drilled through the E-Screw to accept a

syringe nozzle and the poting material can be injected until it is seen to come up into the lead wire

holes. This latter method is better if a series of these Light Engines are to be done at the same


After the potting material has cured and the LED lead wires soldered to the emitter PCB, the

Light Engine is ready for installation into the head.

Although the LE can be installed from the front end of the head, it is best to have the reflector

and window already installed in the head and to screw the LE into the head from the back side. It

should make contact and be snugged against the reflector at the moment that the rear lip of the

ES-Can is flush with the back face of the head. In the case of using a 5W LED where a shim will

be placed between the rear of the reflector and the face of the E-Screw, the LE will need to be

forced further into the head which in turn will force the reflector into the interior of the window

sealing O-ring. If the LE is driven too far into the head, the battery tube will not make a good

ground contact with the ES-Can lip and the light will not function. If the LED is driven at a high

current for extended periods of time, thermal grease should be used to provide better thermal

paths between some of the components. I would suggest the following:

1) place some grease in the bore of the head that is tight against the reflector. When the reflector

is installed, the excess will be forced down into the head and out of the way. Do not place grease

on the side of the reflector as this would be wipped off and left in the O-ring sealing area.

2) place some grease in the threads of the head deeper than where the battery tube will go. The

excess grease here will roll onto the face of the E-Screw and eventually be sandwiched between

the face and the reflector.

Below, is a picture of a BB LE installed in an Aleph 1 head. You can see the external ground wire

used in this build: