Stumped on Dorcy 1AA 3led to lux mod

Ok here's the drill. I bought a Dorcy 1AA 3 led with the intention of trying a lux mod. The thought process that led me to this was the thought that there must be some kind of boost circuit driving those 3 leds. So I unscrewed the head. Peared in the bottom and saw a board with two holes. These two holes accepted a snap ring plier nicely. So I turned, and turned, and turned. hmm no progress. There were what appeared to be threads. Those guts should screw out of there. Well most of you reading this have probably been down this road already. Ok so that didn't work. So I studied the lens end for a while. There didn't seem to be any way in that way as well. So with the aid of an arbour press I pushed all the heads stuff out the front. The lens itself didn't survive this assault but the rest did. hmm no electronics in the head. Just the 3 leds neatly soldered to that previously mentioned board. What's under that black plastic disk and spring? Used 2 batteries to push out what turned out to be the boost board. Cool. Left that aside for now and went back to the head. Filed around the edges of a TVOJ star until it fit into the head. Removed the 3leds from their board. Soldered some wires from this board to the star and placed it into the head. NX-05, a filed down lens from a mini-mag, and an o-ring to hold all this stuff into the head and voila. All was a perfect fit. So I put the original boost board back in and a battery. Fired it up. It makes light but not to impressive. I should add, up this point I had not yet read anything about modding this light. So I searched through many of the postings of Dorcy mods. I was looking for some advice on how to increase the current output. I found very little. There was some mention about removing the resistor. What resistor there are two. Other than that many people talked about 350ma seemingly with much effort. I measured the current at my lux and got 90ma. At this point 350ma would be good. I also tried using a 1/2 CR-V3 battery. No different. What gives?
So I guess what I'm wondering is. Is there something I can do to increase the output of this board to something a little more reasonable for a lux? I can see the potential. It's the answer that eludes me. Can somebody help?

cheers,
zwf /ubbthreads/images/graemlins/confused.gif

If that was a 3V 1/2CR-V3 it should have done what you wanted. BTW, I haven't seen this board. Are you sure there are two resistors on it? Can you post photo?

In all the crunching around you might have damaged the circuts.

The resistor you want to short out is the first one after the positive disk. I shorted mine out and there really isn't a lot of difference in light output.

I believe your problem is simply you do not have a lot of voltage coming out of that single AA battery. If you take your modded head and put it on a 2 AA Dorcy you would really see a jump in the light boost. It would be more to your liking to go with a 2AA set up. The Dorcy 2AA with a Lux and optics is my favorite walking light. It is almost as bright as a Badboy and could be except it has a nicer spill light that dilutes the throw of the light about 10%...just right for walking.

By the way. The single AA and the 2 AA heads are interchangeable.

Dunno where to start here. 1/2 a CR-V3 must be of a brand which uses 2x3V AA in parallel, Eveready is one who does NOT, use Duracell until you find any others. Put a meter to the battery you harvested, I bet it reads 1.75V not 3V, if so you need to get thee to ebay and buy a DURACELL CR-V3 2pk [4 cells should hold you].

The boost-board has a Schottky diode, a few chip-caps and a resistor labeled 1R0, JUMPER accross the resistor with wire-wrap_wire works great. I've been adding some capacitance in the form of surface-mount capacitors harvested off old premium-grade motherboards, usually 22uf at 16V or minimum of 10uf 5V, whatever you can get to FIT. Line on chip caps is + in my experience, where on a diode it would be the cathode or "-" [yah I'm getting rusty]. Someone reported the 2 chip-caps on the board at 1uf Ea., you can benefit from more. You can get caps at DIGIKEY that are up to 10UF that fit that spacing, but I kludge in harvested ones that are larger in value and size.

On a cheaper digital VOM you should read 3-3.2VDC at Luxeon, bear in mind the board is putting out pulsating DC your meter cannot read accurately. I have not measured the current to the LED, but the 1AA circuit driven at 3V after mods lights up a Lux pretty nicely. BEst Lux to use would be one with a low Vf, a 3W is a waste but whatever. As to how I mount my Lux, I thermal-epoxy a metal disc to the top of the battery-tube, it has +/- wires running up through holes in it. When that is set, I solder wires to a raw emmiter and thermal-epoxy that to the disc and quickly screw on the head assy with lense-area facing DOWN. I have already stuck Fraen LP optic in the head and reuse the retaining -ring from Dorcy. The head/optic assy will center the freshly-glued emmiter fairly well in most cases.

SO, what did I miss? That optic retaining ring you can pry out with a eyeglass-screwdriver BEFORE you press all the head-guts out!! The black plastic thing on top of battery-tube, I used to use a screw to screw into it and pull out, it usually cracked the coil underneath [maybe due to expansion of that center hole in the plastic], so now I dig it out with a eyeglass-screw-driver as well.

The Dorcy 1AA running at 3V single AA Lithium w/ Fraen optic is stunning, I will try a reflector as soon as new ones come, I suspect less through but more even beam and some useful spill will result.

I have also added a Lux emmiter to the DOrcy 1AAA light, that is not as huge a difference but well worth performing for a carrying light. Mod the circuit too. It will have 2-3x the spill and light will be white not blue_ish. It that mod I drill the reflector to fit a high-domed lux's clear area.

Someone posted about flipping over the rear button contact under the spring, THAT is a winner thing to do to that light too!! Just did it today.

What else??? If you use any glueing method, test the circuit tack-soldered to a Lux along each step of the way to make sure you are not making a pile of junk. Some have used a dime for the heat-transfer disc at top of battery-tube, it's diameter is just a hair large and will cause you troubles unless resized, like with a wire-wheel on grinder.

It sounds like kd9uu covered all the bases. My edc is a 1AA with Lux III. Mine has the emitter attached to a dime that was sanded down to fit in the battery tube where the black plastic disk was.

My brother in law (BIL) liked it so much that I made one for him. I made his by putting the luxeon star in the head with a contact plate, similar to what Zuluwhiskyfox did. I did it this way so that he could swap the head with a 2AA-4led Dorcy when he wants. That gives him the ability to configure it as a 1AA 4led, a 1 AA luxeon, etc.

Daniel

The Dorcy 'exploded'.

Thanks guys for such a speedy response.
I'm now thinking that there must be something wrong with my board. I have already tried shorting the resistor closest to the center contact. That being the contact for the spring. The CR-V3 I used is a Duracell. I measured the voltage of the harvested cell to be 3V. I think I'm going to buy another light to take apart. Maybe I'll have better luck with this one. Time permitting I'll post some pics tonight.

cheers,
zwf

ZWF, you did not mention the VF of the luxeon you are using. It it a J or K? This is a simple voltage boost circuit, limited by input voltage and the converter's components, so the higher your Vf the less light you will get.

Daniel

Here is an image of what the the light would do with different voltage. I simply traded heads with a 1AA and 2AA Dorcy. You'll see that the 2AA with double the voltage of 3 volts has more light. The photos were exposed to show how a person would see the light. I don't know if it is evident that the light in real time in the Dorcy with more voltage (2AA) is much more useable and makes a nice walking light with a better spill light. The 1AA Dorcy is adequate but not inspiring.

So you can either put the modded head in a 2AA battery case, the way I like to do it because I can find 2AA batteries everywhere, or figure a way to get a smaller 3 volt battery in the 1AA light. I think the second way is more expensive when buying batteries. OK, I'm a cheapskate.

gadget lover, the lux I'm using for this is TV0J.

Have Blue, I here you about the batteries and price. It's more for kicks that I'm doing this. The lights I use every day at work are a mini-mag with a lambda pill TV0J and a arc LS twisty TX1J 560ma fraen. These two lights get a lot of use.

cheers,

Heres how I did mine. Unscrew head, pull out black plastic from body, and solder a wire to the center were the spring was (+) and solder a wire to the metal that presses on the boyd (-). I took a Q3J from it's star board, flattened the board back out, took off the pcb, and ground it perfectly round and installed it in the barrel with wires coming out. AA epoxied the lux on top and wired up. (I tried just cutting the star, but the PCB was shorting out itself)

Then the head I removed the retaining ring, and pushed out the stuff by tapping on it with a screwdriver/hammer.

If you keep the lens in tact you can put an IMS 17mm reflector into it. I took mine and ground it to a flat lens and used a mini-mag refelctor, more work, but that's what I had.

So the way mine works allows you to actually focus it, but I glued the head as it turned too easy for my liking and I didn't use the focusing. Others have put the lux into the head so you can put it on a stock body... but my way just seemed the easiest to me.

BTW if you use a lithium AA then you'll get more brightness. I measure 350ma draw on my used e2 batt.

I also fliped the contact around backwards in the tail switch so it didn't scratch and snag. Momemtary works much better now. (I do that on dorcy 1aaa too)

also check your contact where the lux meets the body. Since I soldered wires directly to my lux to the circuit I don't have this posibility of added resistance.

Isaac, when you say you have 350ma draw, Is that draw from the battery or draw at the lux?

"350ma draw on my used e2 battery." (that's what being pulled from the battery.) So assuming the circuit is at least 80% eff., ~280ma to the lux. Using a simalarly drained alkaline the draw was 100something millamp, I don't remember exactly. So it does make a difference.

ZuluWhiskeyFox,

I just measured the battery draw on my Dorcy with 1/2 of a CR-V3
at 630 to 640 ma. You should be close to that unless you have some added resistance in the system somewhere.

John_bud

Isaac, thanks for the clarification. I've since being doing some experimenting here. On a not so fresh alky I get 180ma draw from battery. On a 1/2 CR-V3 (3v) before shorting R1 I get 560ma draw from battery. After shorting R1, I get 470ma draw from 3v battery. With R1 shorted or not I can't see any noticeabe change in brightness. There is a small difference in brightness between the alky and the 3v battery. However not the change I was expecting given the increase in draw. I don't quite know what to make of this. Any way here are some pics.




/ubbthreads/images/graemlins/thinking.gif

Hey, You do nice work!

Is that a solder filet around the contact board (in the third picture)? That's where the top of the battery tube conducts to the leg lead of the LED.

I noticed with my Fraen that the total light decreased as I moved the fraen away from the LED. Is your optic touching the LED, or is it suspended over it?

It looks like the ferrite around your inductor has suffered the same fate as some of mine. It's very brittle. Can any of the EE types tell me if that makes a difference?


Daniel

It can't be good to have 25% of your iron core inductor broken. That could well be the problem with the low light output.

It might be cheaper to get a new 1AA light then to find and replace the inductor.

The Inductor in that PIC appears to be 47uH value, assuming conventional marking. I'm currently messing with a similar circuit here. Although I mainly designed it to run a single 5mm 5500mcd White Led. It runs off 1.2 to 1.5V, and will run down to 0.8V still with a reasonable light O/P. Scaling the circuit up would enable higher power leds to be used. The current PCB board is 11x11mm, I'll change this to circular shortly. I opted for Zetex transistors, as these have hi-power and a very low saturation voltage (FMMT491A) these are tiny (SOT23) but handle 2 Amps.

I note from your PCB picture that the main power switching transistors is is SOT89 size, this is, in comparison, huge. More experimentation is needed here to see how many watts I can get from a single AA /ubbthreads/images/graemlins/wink.gif

Steve

Zulu, circuit shown in your pic is not what new Dorcy's come with now [ones with crass-hatched rubber grips], plus the busted ferrite can't help. Looks like you added another ~1uf or so cap. Can't tell if circuit YOU have even has the typical resistor labeled 1R0, well, doesn't look like it [whole different beast]. As I recall the newer circuits do not have that extra transistor nor that stray cap. You can get a larger cap to fit in there if you are creative, look for old motherboards or ISA plug-in cards...

I suggest you buy another light, new style with cross-hatched rubber grips, and maybe use the old light with stock head from the new one, *or* add a red-orange Lux to the whimpy one. I have not played with red-orange Lux's however they have a much lower avg Vf [2.95v] and should crank lots of red-orange light out with moderate ma. current. Rated at 55 lumens!! I think the 1AA in red-orange will be quite the blaster, and that the new circuit will light your white Lux better [and mod directions people have posted will seem to make more sense 8) 8) ]