Well it was sweet until it didn't work (you read that part, right?)! It was good practice though. And as I stated earlier, that was my first attempt at stacking 7135's and I found that to be a lot easier than attaching those darn 22ga wires! I never had that slave board fully functional to see if I ended up with the proper current level (i.e. that I didn't burn up any 7135s).
I tell you what though, I am enjoying the quality of photos I am getting out of a camera that I only paid $39 for!
Poor Garry was led astray by a mad duck. The wiring looks exactly the way it should but unfortunately I was mistaken about how simple the swap would be. My bad. Once again, knowing a little will get you into more trouble than knowing nothing.
True but you still learn more from mistakes than you do from things you already know. In a situation where failure is not an option kiss is more appropriate but not for something like this where you can go back to square one with little risk.
. . . I don’t think you have the ability to flash MCUs, but if you did you could use ToyKeeper’s STAR mod which features support for status LEDs. You’d just wire up the 105c to the status LEDs & their limiting resistors on the stock PCB.
Do you know which modified version of STAR has this support? I searched for discussion on the topic, but didn't find any.
Ok here are my measurements at 4.2v battery pack (2 cells parallel @ 4.01v)
off: 0.011A
low: 0.98A
Med:1.30A
High: 1.75A
Now meter in line with LED wires:
off: 0.000A
low: 0.81A
med: 1.33A
high: 1.81A
So I guess my LED measurements are higher because my battery pack wiring & connectors (maybe just my connectors I add to get inline measurements) are adding some resistance. Anyway, I'm pretty much back to stock output. What resistors would I stack / replace? Think my goal was about 3A on high (1.5A per emitter). I know I have R120's and think I have R500's. I have others but I'd have to look.
By the way, I'm correct that the 1.75A I measure gets cut in half for "per emitter" current, right?
Ok, I pulled the R100 and stacked (3) R120's (left other R120 in place). My resistors are supposed to be 0805 size from FastTech and they are 1/2 the size of the ones on this driver. Does that seem right? Is it ok?
Anyway, current on the LED wire is now:
Low-1.32A
Med-1.80A
High-1.96A
I'm wondering now if the LED leads are too thin. Holding the lead up to 24awg wire I'd say its close to the same size, maybe a size smaller (26Awg?).
It may be that the thing has a maximum duty cycle it will not exceed. The new Med/Low currents do seem to indicate that the resistor mod is having an effect. Just not the end result you want for some reason.
0805 sized sense resistors should be OK with 4 in parallel. They are quite small compared to 1206 sized ones, I prefer to use 1206 when I can. Assuming the 0805’s are good for 1/8-watt or greater, there should be no problem with dumping around 0.3w across 4 of them in parallel.
I recommend replacing the leads first. If that helps, great. If not, I feel that you have run into a limitation of the software that came preloaded on that driver’s MCU.
It’s the version discussed in 