Help! flickering sammie in Infinity head (take 2)

[greenLED]

Last night I made a fresh sammie. I tested it outside its host (Infinity) and it worked flawlessly for about 30 sec. I put the sammie inside the Infinity's head and tested it's functioning again... no problems! I had it on for about 5 min and turned it on & off half-a-dozen times; I had no problems. Since it was late I decided to finish the sammie this morning; according to my checklist, I only needed to add the epoxy...

I get up this morning, and just for giggles I put the unepoxied sammie inside the Infinity, turn it on and... it flickers, dims, and proceeds to unceremoniously shut down!! /ubbthreads/images/graemlins/Christo_pull_hair.gif This is exactly what happened to me last time I tried to make a MM-sammie! /ubbthreads/images/graemlins/mad.gif

Last time, Wayne kindly had suggested that I check for cold solder spots, potential shorts, solder only the tips of the LED+ to the connectors, etc. This time, I carefully followed all of his advise while building this latest sammie (it looked suh-weeeet!), and later to try to diagnose the flickering. A full day later, and I haven't been able to fix the flickering...

I made sure not to turn the Infinity's head hard last night while I was testing the sammie. Still, is it possible I crushed some connection/component somewhere on the electronix board?

I've checked, re-checked, done, and re-done all the solder spots and the Lux still powers on, flickers, dims, and goes off.

Now that I've de-soldered and re-soldered the sammie many times, I'm actually afraid that one/several of the components may be broken and I've killed (yet) another converter board.

Why did it work beautifully last night and not at all today? Any ideas? This was supposed to be a B'day gift for my brother, and now I can't devote more time or money to this project. /ubbthreads/images/graemlins/frown.gif /ubbthreads/images/graemlins/Christo_pull_hair.gif Please help!!

 

[jaids]

Re: crushed sammie: symptoms?

Well if anything would brake it should be the inductor. check that out. Also is the pcb cracked?

Use epoxy after testing next time /ubbthreads/images/graemlins/icon15.gif

If it still doesn't work call it it a learning experience /ubbthreads/images/graemlins/grin.gif

 

[knifebright]

Re: crushed sammie: symptoms?

I'm going to agree with jaids on this one. It's all about learning what caused it to blow. I can't even begin to think of all the money i've spent to accomplish the same thing as lighting a match. The important part for me is that each and every time i figured out what went wrong. Things will go wrong in the modding learning curve. it happens. 'The important thing is that you learn what happened and move forward. That being said if your completely frustrated and need a second opionion before calling it dead send it along to me and i'll take a look for you.
jimmy

 

[greenLED]

Re: crushed sammie: symptoms?

Thank you for the support guys, it's precisely not being able to figure out what is wrong with it that frustrates me more than anything right now. AFAIK the PCB's OK... I should check that and the inductor once I get home.

It seems to me that something on the board "saturates" somehow, because the flickering starts after a few seconds of normal functioning. My guess if it were a short, it would flicker all the time, or wouldn't work at all (assuming something blew/smoked). Edit: I just remembered, the very first sammie I smoked simply went out, Lux and all. At least this time the Lux is OK and I may use it on my next build (if I get it off the emitter board, that is...).

When one shorts a sammie, does it blow immediately, or does it flicker like mine does, even after taking it out of its host?

 

[greenLED]

Re: crushed sammie: symptoms?

I checked the sammie and as far as I can tell, the board is not cracked and the inductor is intact. Any other ideas?

 

[dat2zip]

Re: crushed sammie: symptoms?

Can you provide pictures of the host and a possible picture of where you are putting the converter board.

I'm having a hard time visualizing what's going on here.

But, I would suspect that the Anode + on the emitter board is touching the housing in some way. ??? I have not seen it, so, I'm just speculating.

Anyway, if the short persists too long it will destroy the IC.

Flickering could be many things. If it's flickering outside the housing then there could be an intermittent, cold solder joint, open connection...

I'd be happy to look at this if you are willing to ship it to and from me.

I could also try re-creating the mod. Where can I get one of these lights? What does the mod entail?

Wayne

 

[knifebright]

Re: crushed sammie: symptoms?

Hey wayne
if i'm correct greenled is trying to put a sammie in an infinity. The infinity head needs a little boreing. I've made many this way. However if material was taken off of the sammie instead of the can then many other things could go wrong. Also In this mod if the connector wires are even slightly higher than the led base there is a good chance that the anode is making contact with the ground path. I've made a good 6 of these mods and made everymistake that i thoguht was possible in the process. One more thing could be the short stack sammich could have undue pressure on the inductor. I was thinking though from the description that the cold solder joint may be the culperate.
jimmy

 

[greenLED]

Re: crushed sammie: symptoms?

Knifebright's right, I'm trying to put the sammie into an Infinity.

I quasi-short-stacked the sammie, leaving 0.5mm (0.02") space between the top of the inductor and the bottom of the emitter board, and not reducing the thickness of that board. I did not file the converter board as I originally intended to. I did, however, file the emitter board's OD slightly to fit in there, since I wanted to avoid boring the sides of the original Infinity can (I'm boring by hand and am new to the whole Dremel thing). Total sammie height is 6.5 mm (0.256").

I measured the insides of the can last night, but left my notes at home (then I left my lunch in the class I just attended... /ubbthreads/images/graemlins/jpshakehead.gif) At least I brought some pics! From my measurements, I am sure I have enough "head clearance" between the top of the connectors and the bottom of the can ("bottom being closest to the reflector side). Please note there isn't much in the way of solder on any of the contacts because I took the pics after one of my desoldering attempts, but I can tell you my original solder points were small and located towards the Lux'x base:

This shows the inside of the can. Only the Lux dome protrudes through the hole. The black Lux base rests on the floor of the lower space. The lower "lip" supports the emitter board and provides the NEG path for the emitter board. Most of the lip is around <1mm (0.04"); but I measured an area with about 1.2-1.3mm (0.047-0.051") lip last night. The "middle" can is the unmodified space in the stock Infinity head. The upper lip is where the MM board rests.

Pic of the space between the inductor and the emitter board, and one set of connectors. I actually pushed them +-0.5mm lower than their stock length before initial assembly to reduce the chances of a short.

Here are the other set of connector leads:

Thank you very much Wayne and Jimmy for taking the time to examine these pics and my measurements and helping me out.

 

[dat2zip]

Re: crushed sammie: symptoms?

What I usually find is the Anode connector pins that stick up on the emitter boards short to the inside wall.

I've marked your image with a yellow arrow.

I would measure this diameter. I bet there is not much space there and I suspect that the sandwich can move laterally back and forth some which could push the anode contact against the side wall shorting LED+ to GND. This will cause intermittent (no light) when it shorts and working light output when it's not shorted and of course if shorted long enough it will blow the IC.

I would suggest in tight mods like this to paint the LED+ connector and Emitter lead. After inserting it a few times you can inspect the paint to see if any has been scraped away or has been deposited due to scraping on the flashlight housing.

If you find paint removed or transfer, you can permanently use some good epoxy or something to help maintain isolation, but, you will over time might require a little refurbishing of the epoxy if it wears down.

Thanks for the pictures. That helps a lot.

Your sandwich looks great! /ubbthreads/images/graemlins/happy14.gif

Wayne

 

[rdshores]

Re: crushed sammie: symptoms?

If you look at the area I put a box around in the following picture, you can see that the solder is flattened right on the corner like it had pressed up against the housing like Wayne said. I believe this is the LED+ lead. I bend those pins in tight to the LED before soldering and then put some epoxy over them.

 

[greenLED]

Re: crushed sammie: symptoms?

Thank you gentlemen for looking into this for me. I took a bunch of measurements last night and it seems like the clearance I left between the emitter connectors and the walls of the "can" was not enough. Most of the can is big enough, but there's a small area where I missed my target for about 0.5 mm. This is probably where the short was.

I'm guessing what happened was this:
- I built the sammie OK (as it worked fine out of the host).
- The first time I put the sammie in the can it worked OK too because, by chance, the + contact missed the area with insufficient clearance.
- The next time I put the sammie in there, I wasn't so lucky, and I shorted the sammie. It's all downhill from there! /ubbthreads/images/graemlins/smile.gif I had not covered the + leads with anything.

For my next attempt, I will bore the can a little more as Wayne suggested; probably leave a lip of approximately 0.75mm. (knifebright, do you leave a lip at all?) I'll also bend the contacts inwards as rdshores suggests (thanks! great idea) and cover the + leads with epoxy too. Hey, I can never be to careful now!

For future reference, is there a way to check for shorts with a DMM?

Jimmy and Wayne, I appreciate your offer to check out the sammie. Unfortunately, it moved onto "circuit heaven" late last night. /ubbthreads/images/graemlins/frown.gif I guess the IC could not take any more flickering torture from me. /ubbthreads/images/graemlins/smile.gif The Lux survived.

 

[greenLED]

Re: crushed sammie: symptoms?

knifebright, do you leave a "lip" on your mods to serve as NEG contact? I'm thinking of leaving one that is <1mm.

 

[knifebright]

Re: crushed sammie: symptoms?

Ya on two i've left a lip but i go the epoxy route once i'm certain that the sammie works. also a split ring from the mag solitaire included key chain will make a really nice quazi lip that not only will complete the circuit but not short out the leads.
jimmy

 

[greenLED]

I need help with the infamous Infinity mod. I can't seem to get this right.

I bored out the head some more so that there's *ample* space to prevent shorts. I also covered the (+) lead with nail polish and then some epoxy (which later got coated with GID paint).

I built a new sammie. I tested it outside the host: no problems. I epoxied it for crush resistance. I tested the sammie inside the head: no problems. I was playing with it for an entire day: no problems whatsoever. I turned it on/off repeatedly, and I also kept it running constantly for a little less than 2 hours at one point. No heat issues, no flickering... perfect!

Yesterday I decided it was time to add a shortened NX-05 to get a tighter beam (what a difference, BTW!). I epoxied the optic onto the Infinity's head: I got it almost perfectly centered on my first try! Nice beam /ubbthreads/images/graemlins/grin.gif

I have no crimp left on the head, and I bored the top walls of the Infinity's head a little to fit the converter board, so there's a gap (more of a step) between the MM board and the host's aluminum. Since I had a bit of clear epoxy left, and I the light had worked flawlessly, I decided it would be a good time to pot the sammie in the head for good. So I put a little bit of my left over epoxy into the gap I just mentioned.

I let the head sit for about 2 hours before touching it again. Finally, I couldn't wait any longer so I assembled the light and... it *flickers* /ubbthreads/images/graemlins/Christo_pull_hair.gif [censored]

I rapidly conclude that the 24-hr epoxy I used was too "runny" and got down to the (-) contact on the emitter board. I desperately scrapped off the epoxy (still not hard, but very gooey) and after some struggling, I pull the sammie out intact. (At one point the image of a power drill flashed through my head /ubbthreads/images/graemlins/grin.gif, but I did not give in to temptation.)Indeed, the epoxy had run down between the sammie and the can's walls.

I carefully scraped off the epoxy off the walls of the can and the surface of the emitter board. I cleaned stuff with alcohol. I sanded the top of the emitter with 1500 sandpaper and used alcohol again. Put the sammie back in the Infinity's head and it flickers!! /ubbthreads/images/graemlins/Christo_pull_hair.gif I test the sammie out of the head and it also flickers!! I hasn't stopped flickering, no matter what I try. I'm actually afraid the MM board is (once again) toast. /ubbthreads/images/graemlins/frown.gif

What in the world hapenned? Is it that once a sammie starts flickering, it's DEAD? This flickering was not from a short, though, but from a poor (-) contact. Or so I think. I've been trying for several months to get this right and it's just not working. You guys make it sound so easy! Or is it that you cheat a little and only post your successful mods? Come on, you can tell me the truth... /ubbthreads/images/graemlins/smile.gif

whew! That was quite a rant. Thanks for letting me share this with you. For a little more than a day, I really thought I had a successful mod this time. RIP, my old MM friend... /ubbthreads/images/graemlins/smile.gif

 

[knifebright]

Tell ya what i'll make you feel better. I built up another one this weekend with a madmax+ and a lux3. My very last infinty ultra-g. Epoxyed it in with five minute epoxy. Tested it out after 10 minutes and it would only work if i tightend it down really hard. THis means that the negative contact was not solid enough. It also means over night after the epoxy really cured that the light wouldn't work at all. Now i've got a completely dead light and i'm going to either have to .....save the emmiter and cut it out of the head..... or save my very last ultra-g head and drill out the emmiter. The moral of this story is just cause i may know what i'm doing with this particular mod doesn't mean i'm not going to screw it up. These are some seriously tight tolerances with many oportunities for stuff to go wrong. Don't be discouraged. You should see my grave yard pile from mod's gone wrong. You 'll get it just don't give up.
jimmy

 

[greenLED]

Re: Help! flickering sammie in Infinity head (take

/ubbthreads/images/graemlins/awman.gif that did make me feel a bit better, in a sick and twisted sort of way. Thanks for sharing! I see all the modders posting these fantastic creations, but I'm starting to realize only the successful mods get shared.

So, once a sammie starts to flicker, is it "gone" forever? Is there a number of flickers (or flickering for some definite period of time) that kills a converter? /ubbthreads/images/graemlins/icon3.gif

 

[knifebright]

Re: Help! flickering sammie in Infinity head (take

the flickering sounds like you could have some epoxy creating a poor negive contact. try to scrape the emmitter board clean with a razor.
jimmy

 

[Takifugu]

Re: Help! flickering sammie in Infinity head (take

Hi greenLED,
Have you tried testing with a new cell?
I have build 3 infinity Luxeon mods (2 old and 1 new type infinity).
One of the mod would flicker whatever I do but found out that the reason of the flickering was only because the battery had been drained /ubbthreads/images/graemlins/banghead.gif
Sometimes I seem to ommit checking the simplest of problems.
Sorry if this is not applicable to you, but just thought I would like to share my experience and hope it may help.
Regards

 

[greenLED]

Re: Help! flickering sammie in Infinity head (take

Thank you for your encouragement and sharing your fixes. I was so frustrated that I shoved everything back into my toolbox and haven't looked at it more closely. I will scrape the emitter board, and check with a new battery. Of all the things I checked, I did not do the obvious... /ubbthreads/images/graemlins/stupid.gif /ubbthreads/images/graemlins/smile.gif

 

[dat2zip]

Re: Help! flickering sammie in Infinity head (take

If the flicker is due to poor gnd contact, then there should be no damage to the sandwich module. If the flickering is due to the LED anode contacting GND and shorting this pin, then at some point the module may just give up and let some magic smoke out.

Sorry to hear about your troubles and I'm glad you are sharing this with us. I believe you will have saved someone else some major headaches from your experience.

Wayne