I tried measuring the current in my tk-61 by cutting the negative wire and attaching the dmm in series to that wire. It didn’t seem to work to well I was getting reading all over the place and the light would kinda fliker it just didn’t look right. Anyways, I was wondering if that was the proper way to do it. Also, after I tried that the led only worked on low mode then it just went out. I dedomed it at I may have bumped one of the wires to the led. Is there any way to test an led like that to see if it’s making a complete circuit? Also, the light said it was reading about 4volts at the led mcpb but when I changed modes the volts did not change. Nothing in the driver burned out so I’m not really sure what happened. I also tried reflowing a different led onto the mcpb and that did not work either. I guess both the leds could be bad I have a spare tk-61 but I am afraid to hook up the other mcpb with the led on it. Any suggestions to what may have happened?
Hi, looks like you are one who followed the Tk61 racer86 mod thread. I also modded mine at first when I put a R025 sense resistor on top of the r050 resistor, after just a minute of switching it on turbo suddenly it flickers the emitter, then I got only the low mode now and when I look at the PCB again one of the transistor C01C blew up, burn :_( . beside the sense resistor. I was lucky to find another transistor and replace it the C01C, after that I remove again the R025 and change it with R050……and it everything works. I am getting 4.3amps on the emitter now. Hope it helps. cheers
Yes, but only if the dmm+wire chain inserted has a neglectable resistance in comparison to the LED+original wire chain (which is quite low already).
Why would this be a problem? The main thing the driver does is just applying the required voltage to gain a fixed, given current.
More resistance in the chain means more voltage required to gain same current. And this certainly also means more power altogether. The driver might just choke if you inserted too much resistance.
After I had problems with tuned lights and a dmm I switched to clamp-on amp meter. Here you only have to insert a short thick cable so you won't change resistance notably.
TK61 w/o resistor mod: 3.05A, with 25 mOhms: 5.26A. It's getting irregular with these low resistances, though, because the overheating mosfets become the bottle neck.
Try to measure the forward voltage, that is measure both current and voltage (as near as possible to the LED itself) at the same time. And compare with the datasheet.