Solitaire- qtc fail - 7135 Hotwire success - Pics and beamshots added

The optic cracked. I think it would be better design wise if the pressure applied to the qtc pad did not include things like optics and batteries in the pressure path. I’m making up a new pill with 2 - 7135 chips to regulate and simple on/off twisty. I’ll update the thread with the original bits along with the new bits as time permits. It was nifty but I didn’t get it quite right. Sorry ChicagoX, it won’t be a qtc.

This being my first attempt at using a qtc pad I’m not terribly disappointed at the failure. Especially since the light turned out well in spite of that. I had hoped to be able to endow the the diminutive Solitaire with both nicer output and output control but for the time being, I’ll settle for the output. On to the build.

While dinking around I had noticed that a 3/8 copper bushing fit nicely over the Solitaire body but wanted to use something more corrosion resistant and Justin’s use of metal trim bands in his marathon thread made me think of brass hobby tubing. It comes in 12” lengths and each successive size is a slick fit into or over the next size up/down.

I cut about 9/16” from each of the 3 lengths and soldered them together. Then, fitting them onto a 7/16”x 1 1/2” bolt with some heat shrink tubing layered for a snug fit(had to use silicon grease to slide the blank into place). I chucked this into the drill press and using a hacksaw blade screwed to a block of wood, cut notches in the blank. This worked better than expected with plenty of room got improvement. I set this aside to wait until I knew the stack height of the led pill.

I wrapped the body with tape and marked the tape where I wanted to make the cut, leaving ~2/3 of the thread intact. I assembled the light with the optic, the led, and a cu disc for the pill to see how much gap the brass sleeve would need to cover. Then, having removed the delicate bits, AA’d the brass in place cleaning the excess with B-12.

The original led pill copied Justin’s design except I widened the hole in the battery tube to 5/16” to allow for more cu and beveled the hole for the solder.

The qtc was bothersome, then troublesome, then a failure. Not because it didn’t work but because the force needed to induce the quantum tunneling effect was greater than the plastic in the led holder could tolerate. I had hoped to use a small, stiff spring to obtain some control but had to nix that plan in favor of the pad embedded in a cu sandwich with a cu post as locator conductor. The sandwich is held together with sikaflex, a tough, flexible caulk.

After the failure I went to plan B, long in my mind as an option for small hosts. The 7135 Hotwire Mod:
1st I AA’d together two pairs of 7135 chips( the second for when I cook the first) and set them aside. Then on to the pill. If you have scrap cu it’s pretty simple but tedious. Cut the cu bit you need and heat it to remove its temper.

Flatten it by any means available, and snip the corners. Then file it round.

With no cu tube on this pill I added an extra layer plus another piece for the battery+ contact, laid down a bed of solder, drilled it for the wires, and lapped it .

Although unnecessary this time, this next step is why I made 2 pairs of chips. I clamped the disc into the vice and put a drop of flux in the center and heated it from underneath with a small butane torch. When the solder melts, carefully place the pair of chips into the solder ground tabs down and the ends lining up with the holes and remove the heat.

Solder the wires to the pcb, add adhesive, and thread the wires through the disc making sure to align them with the correct ends if the chips. Then trim, tin, and solder the wires. From here out it gets ugly.

I did not have a nice sleeve to put over the chips so I reused some heat shrink tubiing and filled the void with Fujik, then soldered the positive contact in place and filed it smooth. Since the optic holder was cracked I decided to go ahead and pot the lamp assembly into the head of the light in hopes that it will all stay put.

Finally, I had to replace the qtc with a spring. This involved more sizing, cutting , filing, reaming, and soldering but in the end it worked out okay.

Tail cap current measurement was 680 mAs.

Left :AAA Solitaire, center:AAA Minimag, right: Solitaire with qtc

Left:AAA Solitaire, center:AAA Minimag, right: Hotwire solitaire

Reserved

Bumped for a good cause.

Nice work with the 7135s! I just got a 100 pack of them and they are a pia to solder.

Working with those tiny parts is a PITA, no matter how you do it. I am firmly convinced that the solitaire is a useless light, designed to irritate modders and accumulate more metal scrap in dumpsters. As a stock light, it has no purpose and as a modding light it leads to an increase in first aid supplies and cursing that shouldn't be heard by sailors. Kudos to you, for trying to play around with one. I will never touch one again, LOL.

Well it your fault I’m doing it. Dammit! If you’d stop making all that cool stuff, who would I have to copy? Seriously though. If you can reflow a Nichia, you can do this mod. I have 2 more Lisa optics from Newark.

I just saw this thread, and I gotta say "wow!"

I do not have the patience to work on the tiny stuff; I admire your willingness to go at it, twice. I would have just circular filed the whole thing after cracking the optic.

Well done, and a big thanks for the giveaway.

One distinct advantage is it takes longer to fill up the bin.

Its a shame the qtc watchamecallitthingymabob did not work. I'm having trouble downloading the pictures but what I can see looks like your perseverance to get a working light paid of.