2 bad dd mag mods- what am i doing wrong?

[jasonsmaglites]

i finished my 4d dd high vf led mod and it should be putting out 700ma as i tested it with 4 d's and that's what it was getting right off the bat. however the light came on, shone nice and bright with a flood of light, then went down to about the brightness of a fenix eo1, if that. also a light i built 2 months ago, a 2d low vf dd which was nice and dim, with insane runtime (probably) has had flickering problems since about a week after i built it till now. what could i be doing wrong. the only thing i can think of happening is that i am drilling h22s holes a little bigger to fit my wires through and im grounding out the positive since the inside of the heatsink isn't annodized. i really dont think its that since the plastic sleve should be isolating it. and on my 2d, it seems like it is in the switch that the problem is. could i have put too much solder on the switch and found a ground from the positve solder? (by the way, in a mag switch which is + and -, the tab we fold over or the piece down in the center) i can't figure out what im doing wrong. i've had other builds be fine, but some of them are sold and gone, and i have a red 3d here at the house that is beautiful. can anyone offer suggestions for common mistakes for these mag sscp4 builds?
jason

 

[dirtech]

The center of the mag switch is + and the metal tab that you fold down is -. I can't answer your other questions. Good luck!

 

[Aircraft800]

It's hard to tell. The center of the mag switch is the positive. It should be easy to tell since the long tab you speak of that you bent over is connected directly to the ground set screw. There is no mention of a driver of any sort, and if you are running DD with no type of resistor or anything if using alkaline is 6+ volts, on NiMh 4.8+ volts, probably a little above what that sscp4 was ever made to handle.

Do you have a multimeter that you could test your LED and connections? Just to play it safe, it is always recommended to test polarity and if the "+" wire is isolated from ground before applying power.

 

[^Gurthang]

Did you use a dropping resistor to limit the current draw w/ the 4D? Sounds like you over-drove the emitter.... I've done the same thing.

The flickering 2D, have you checked your solder joints? Could be as simple as a weak connection. Good luck w/ you diagnostics.

 

[jasonsmaglites]

the led now on the 4d mag was in a 3d pulling .2 amps. i moved it up to a 4d and tested at .7 amps. just a very high vf. its dd. no resistor, variable resistor, or driver. as far as the 2d, it is the same led i believe, but different symptom so i dont just attribute it to the led. we took the 4d outside and it worked for a few seconds but went almost immediately down to 2 lumens or less. inside the house it was powering up fine. if it was grounding out would it have power for about one or two lumens (barely lights up)?

 

[old4570]

Check everything ! ..

Pull it apart , check everything ..

If it was a short , current would go up up up !
Current going down ? Sounds like a bad connection . Or the LED is fried .

Check LED's with CR123A or 18650 , if they light up fine ?
But check current at the tail when the problem occurs ..
If the current jumps up , its a short , goes down , LED or bad connection .
And the batteries , are they OK ?

2D = 3v , what is the vf of the LED ? , and what batteries are you using ?

SSC P4 ... Did you isolate the base of the LED correctly ? are they on stars ?

 

[Al Combs]

Which H22A did you get? Was it the type III anodized or the bare aluminum? The metal core on the back of the SSC-P4 is positive. A bare metal heatsink could be your short. After you jam it in the MagLite, a small scratch in the battery tube is all it would take. Did you check if the LED slug is grounded out? With the batteries removed and the switch off, you should have high resistance between the LED anode and the MagLite ground. The bare metal part by the battery cap would be a good place to check.