Thanks guys!
I found that some of the pad placements were forgiving where the pad was adjacent to a “like” contact but that others were difficult to avoid bridging.
DBCstm, as usual nice pics. It looks like you did a better job than I keeping C1 and R1 discreet. I had the same issue as Nitro and more than once had to remove a component and replace it. I was just happy to find out that programming isn’t lost with resoldering the IC.
Those are really good pics Dale. I think you might be light on solder for the 7135 ground tab. That exposed gold area should be completely tinned.
Nah, doesn’t matter. Chip is only doing 350-380 mA. You could get away with no solder on the tab. There is not enough metal under the chip to do much help with heat sinking…
Yeah but with no solder is it even connected? I’m not concerned with heat sinking son much as circuit path continuity. The lower diode pad might be suspect too. Why I suggested the meter first.
Question: Does the programming just blink for low voltage or will a break in the voltage ladder cause the IC to interpret low battery condition and shut down?
I’ve gone over every connection, I’ve added solder to that chip ground tab, I’ve tested continuity where I knew it was supposed to be, followed trace circuits testing continuity, I’ve replaced resistors, capacitors, everything but the mcu itself, which I’m believing now is at fault. All 8 legs of the mcu have really nice joints, just cannot get even a glow from the emitter, which I’ve tested repeatedly and it pulls over 3.4A through the protected 14500 I’m using when tested in direct drive.
Just no deal. After several hours testing, I smashed it with an 8 lb sledge. Works for me! 
(I didn’t , of course, but have wanted to!)
Phooey. Well, besides making the little $&@/ bigger, think about what made it extra difficult for one part vs any others. Were there any you thought weren’t as hard? Oh yeah, one last bit. A pic of how you wired it please? :*
I can’t believe I missed this until now. I have been wanting to make a “Real” penlight for a long, long time. Will these work with an SMD button/switch? Where do things stand? I would really like to get in on putting some of these things together.
Also after looking at DBCstm’s pics I was wondering if a high temp silicone mold was made of an assembled side of this driver, then could the bits and pieces be placed in there dabbed with paste then carefully apply the MCPCB and the other parts and just reflow? Obviously I’m still a toddler at this stuff so have patience with me.
Does anybody know of good 10mm TIR’s? Sorry I’m giddy with excitement seeing all the great work ya’all have been doing.
If you soldered/connected the middle pin it is. That is the preferred connection to the chip ground. The tab is mainly for heat conduction.
I wired it to 2 bulls and waved a red flag. 
I’ll get a pic, but it won’t be pretty, the bulls are really stirring up some dust!
I tried a lot of things. It has a smaller capacitor to ensure both ends were connected, smaller R2, smaller then removed and bridged R1, bridged R2, I’m tired.
No magnification. Tweezers, small curved hemostats, and a toothpick were used. Had it worked right off the top, I’d have said it was easy. In retrospect, I did not take a brand new driver apart…which is probably the problem. I didn’t have a driver, Richard is out of drivers, Intl-Outdoor is shipping drivers on a boat going the wrong direction. So I improvised. And of course, regret it. I will try again tomorrow and de-populate this one, remove a driver from a light and start over. With some alcohol. A quart.
Maybe I should point out that the Qlite was actually potted in Arctic Alumina Thermal Adhesive when I started. Yeah, I know, glutton for punishment…
No worries. The elevator hasn’t left the ground floor. This is just a beta test of the first few boards to see how we might improve them. Matthaus has already done a new layout but I want to get some feedback from the other beta victims before he shows it off so there’s plenty of time. In fact, you’ll still have to wait a bit longer to even ask but please stay tuned. I can’t remember but it’s either the Tina or Lisa optic made by Ledil that’s a 10mm tir. Mouser has them.
Adding the TIR to the mix makes neat sparkles in the pcb dust when you crush it all together with a 16 lb sledge.
Could you stack the 7135’s, I saw a image here of someone literally puttng a 2nd one on the top and bridging the legs
How-To: Add 7135 chips to a Driver Board (Stacking)
Yes, you can stack the chips. Provided there’s room for that in your application of course.
Yes, stacking chips was part of the design plan since there isn’t space on the board for more than one. A solitaire has room for 2or 3 easily(well, nothing fits in a solitaire easily) and a AAA Minimag could fit as many as you can stack in a straight line. I wouldn’t go over 4 in something that small but you could.
Dale, good grief man. I extremely sorry if I put undue pressure on you to get to this before you were ready. I’m amazed at what you did without a lens. I wouldn’t dream of trying. I can’t even see the markings on the diode to tell which way it goes. Even with oculary assistance it took me a few tries to get it working. I use one of These but 5x is just barely enough and a floor model or one with a longer goose neck would have been better. When was your B-day? Seriously, might as well attempt open heart surgery with a spoon like Alan Rickman. You deserve a medal. Sheesh.
No pressure, just having fun with it as you well know that these teeny tiny things can bring frustration levels soaring. Want others to know to have the BFH ready, just in case! 
I’m nearsighted, wear glasses of course, and remove the glasses to view things close up. From about 7-8” away I can see real good! My 18 yr old daughter says it’s a mad scientist look, hovering over the work piece in stoic concentration. lol
There’s markings on diodes? They go a certain way? Are you serious? Well I’ll be forever…
Of course I knew this, I’ve done plenty of zener mods by now. I took careful note of how everything was on the original board, kept a visual aid nearby for confirmation, did it all “by the book” and failed. Oh well, today’s a new day. I’ll try again and if I fail again I’ll hook it’s beastly little ornery a to mains!
At 51, I’m just really glad I was actually able to hold the soldering iron still to do this! My narrow tip that I ground down from a 2mm bevel tip isn’t working for some reason (left it on for 8 hours by mistake, would that do it?) so I actually did this with a new 2mm tip. Got a little tricky double and triple checking contacts but…
You can’t grind down soldering iron tips. They are plated. Break the plating and the solder starts dissolving/pitting/eroding/screwing up the copper core of the tip.
Been using this ground down one for months stacking chips, probably done a few hundred chips with it. I tried to order one smaller and got the same one I had, so I just ground the old one down on the sides to make a 1mm wide bevel tip. After leaving it on accidentally, it wouldn’t melt solder anymore.
Guess I’ll try again and order a small one for those tiny places.
(Didn’t grind it, actually filed it down)
There’s a line on the board that matches up with the line on the diode. At 54 my eyes no longer focus at 7-8” the way they used to and from 2’ away … well, let’s just say the lamp really helps and leave it at that. Your suffering is not pointless. It’s good that others know that while this can be done with the right tools there is a learning curve to smd soldering and if you’ve never done it before don’t be surprised at how messy the first few attempts might be. I don’t have a hot plate and my small butane torch with the catalyzer tip still has a tendency to turn parts into smoking ruin so it’s the fine tip and magnifying lamp for me.
After leaving it on that long you probably need to dress the tip with a file and retin it. It would have an oxide layer that solder won’t wet to, just bead up and slide off. My first Weller iron had a 5/32” pencil point that I ground to a curved point and after leaving it on (or just using it all day) it would develop bare spots and behave in a most frustrating fashion(the last time I used it I left the tip buried in a plank). The tips on the Yihua 937D have some kind of coating that prevents this but I’ve heard that the coating does wear out.