I finally have a powerful enough soldering iron to open up larger lights and boy did the NOV-MU require a lot of heat.
I want to have an option to enable the switch LEDs without charging because I’ve sometimes had difficulty finding the switch in the dark. I’m documenting this process because I’ve found Tom E’s tear down and modding photos really helpful when opening and modding lights on my own, particularly the first few times I modded a light. Thanks Tom E!
I used a big C4 T12 tip cranked up to 400C and just dumped heat into the head of this light to desolder the mcpcb wires. This light has an exceptionally good heat path from the mcpcb to the head and I had to wear gloves because of how hot the head got. My EC03 with a bigger mcpcb doesn’t take nearly as much heat.
There was a lot of thermal paste under the mcpcb and shelf is more than a centimeter thick, about 1.1-1.2cm.
I’m not quite sure what material the mcpcb is made out of. The bottom has a colour like that of brass, but very dull like you’ve turned the saturation in a photo down. The sides are a grey shiny metal which makes me think aluminum. The mcpcb is also very lightweight compared to other mcpcb I’ve held. This isn’t a DTP mcpcb because the E21As don’t have a thermal pad, but from how much heat I had to dump into the head, and how hot the head got, I’d say the thermal path is excellent.
Here’s a look at both sides of the driver. This is Fireflies’ new 6A buck driver designed by Loneoceans which fireflies is presumably using in all their new lights. Some lower powered lights like the T1R will probably have the fet disabled.
It includes the two resistors to enable C-C charging.
Here are the components I’ve identified
It uses two identical p-mosfets, one for Reverse polarity protection and one to do switching things.
I left off tonight with analyzing the switch LED leads and how they connect into the charging IC.
One thing to note is that the switch LEDs share a common anode (+) instead of the usual common cathode/ground (-) of aux LEDs.
This complicates things since both LEDs connect to VCC of the USB charging, and I can’t just connect an attiny1634 pin to the VCC of the charging IC because that would result in…
since the battery would then be charging itself (I think).
So I believe my best option is to connect the common anode to an attiny pin, the blue switch LED’s (-) to ground, and keep the red LED’s negative connected where it is right now, as an indicator for the charging.
This would result in a blue switch LED which I’d have to figure out how the programming for, and a red charging indicator LED that can only be turned on when the blue LED is also on. There might be a problem with this arrangement but I don’t have the electronics knowledge to figure out why this shouldn’t work.
A more pressing issue is the fact that the Attiny 1634 is on the opposite side of the driver and I can’t just connect a pin over from the spring side to the top side of the driver. Loneoceans did write that there were several jumper pads unused in his github code but I haven’t investigated where those jumpers are or if they even exist.
It’s a bit tricky because I think this is a pcb with more than 2 layers since some drilled holes just exist with seemingly no connection on one side.
Anyhow, that’s an adventure for tomorrow and I just wanted to get this out here since I don’t think we’ve seen any pictures of fireflies’ new driver.