Quick question… does anyone know how to remove the driver from a Convoy S7 pill? Or, from pre-built Convoy S-series lights in general?
I can’t quite tell how it’s attached. I don’t see any solder holding it in, but there could be some glue. Or it’s possible that they might have soldered the driver to a retaining ring and then screwed in the retaining ring on the inside of the pill (seems unlikely though, because how would they get the lead wires through?).
I just want to reflash the firmware on a driver or replace it with another driver, but I can’t get the thing out of the pill.
Oh, er, that threaded ring is actually the pill. I took the picture with the pill resting inside the head of the light.
I’ve tried to pry it from the notches. I took out the emitter star and tried to press the driver out from the other side. I put it on top of the stove and tried to lift it out after it had gotten hot enough to melt all the solder on the driver. Nothing has worked yet… it seems really, really stuck.
I haven’t tried to press it out while it’s solder-melting hot though, since I don’t have a way to hold it solidly when it’s that hot. Trying to pry the edge up at that temperature had no effect though.
I’m pretty sure my old driver is dead now, after getting the entire thing hot enough to melt the solder while the components were all hanging upside-down. Gravity may have removed some chips for me. But I still can’t get the thing out. I’m considering just hitting it really hard with a nail to see if I can crack it and take out the pieces.
Flip the driver over and sit it back in the head, then use a piece of coathanger or other suitable wire, down through one of the wire holes in the top, and tap the driver out the other side.
Odds are, that it’s a press fit. I can see no traces of solder between driver and pill.
I’d unscrew the pill, desolder the led-star and then push through one of the cable holes with something broad enough to just fit through the hole but with a flattened or slightly rounded surface to keep the driver unharmed… hopefully.
You can use a spare 105C to look where you can push without hurting any component.
I managed to get the driver out. I ended up screwing a drywall screw through the center of the driver, putting on some thick leather gloves, and pulling on the screw for all I’m worth.
I first tried to hammer a nail through from the other side, but even that didn’t do much. I’ve never seen a driver quite this stuck before.
After getting it out, I discovered something a bit odd… there’s a third wire inside, one side soldered to the ground side of a 7135 chip and the other side looks like it was soldered to the inside of the pill. Perhaps that’s how they got the negative contact to work… instead of just putting a blob of solder between the outer ring and the pill.
In any case, it’s destroyed… but it’s out. And I can put in a new driver now. As a side effect, this will also upgrade it from 350mA 7135s to 380mA ones, along with the new firmware I’m giving it.
Good you got it out eventually. I usually solder a wire from the -trace to the inside pill for a more secure better connection, seen this on a few lights i’ve modded, if it’s an aluminium pill sometimes a small screw is used.
I think it was a very tight press-fit with some solder on the inside of the pill. Not sure how they managed that one. I think there may also have been a bit of glue, but it’s hard to tell for sure.
There was a wire from the driver’s ground ring to the pill, and it looked like the driver end of that wire was also soldered to the pill. But it’s possible that part could have soldered itself to the pill while I was trying to loosen the driver with heat.
In any case, it’s out now. I don’t mind losing a $3 easily-replaceable part in the process. And now it’s using a nicer driver anyway, filed down to let me take it out easily for reflashing.
In case this is useful to anyone else, I just took apart my Convoy S2+. The pill has two square tabs like the ones in ToyKeeper’s photo. I bent an old coat hanger into a U shape and filed down the ends until they fit in the tabs, and was able to unscrew the pill from the host. Next up, there was a retaining ring screwed inside the pill to hold the driver in place. The retaining ring had two circular holes on top, so I filed down another piece of U-shaped coat hanger until the ends fit in the holes. After scraping away some of the glue and cursing a little, I was able to unscrew the retaining ring, freeing the driver (try and keep the driver from turning as you unscrew or it will twist up the red and black wires that connect to the LED, possible ripping them loose).
So, after some effort, I now have the driver loose and ready for upgrading. The driver in my Convoy uses an Atmel 1350 Tiny13A, so I should be able to reflash the firmware once I get my SOIC8 clip and USBASP. Good times…
Awesome. I love it when they use a retaining ring instead of solder. It makes things so much easier! (and also means I can easily reflash later without leaving the driver loose)
To unscrew pills and retaining rings and such, I’ve been using an old pair of machinists calipers (dividers). It works really well:
I hope you’ll have fun with the firmware when you get there!
Calipers are a BRILLIANT idea! I’ll have to try and find a pair.
I presume that there is a dedicated tool for this sort of thing. It reminds me of some specialized tools for removing the bottom bracket (pedal crank bearings) on certain bikes…
EDIT: Yup, retaining ring pliers are a common tool. Lots of sizes and configurations though, so not sure what is best for flashlight tinkering….
I have actually sacrificed the blade of an XACTO knife…they are glued some how, just put the sharp side in the divide between the driver and the brass pill…tap it down thru the gap, once deep enough gently pry it off, the calipers or a very thin/small flat blade screwdriver is also a good idea! the trick is to get below the driver and gently pry up, this is why some driver designers put a hole/divot/notch in the side of the driver in case someone needs to put a dental pick or something in there to gently persuade a stuck driver out of a pill
The X-acto trick would be great for press-fit drivers, but what about threaded drivers? The ones I was looking at today were all threaded, so I don’t think I’d be able to just pry them up and out…
