Hot FoC Resistor

[KongoBongo]

Hello folks.

Seeking some help trouble shooting my first build.

I jumped the pad on the PEX with solder and a bit off the trim wire of a resistor. I then have a 0.5 ohm 3w resistor on the positive off the PEX to positive on the NB board. The Foc die is white. When I take the kill key out I get the boot sound. When I turn the momentary switch on, I get non stop swing sounds and that resistor gets very hot after only about 5 seconds being on. I get no FoC activation either. After reading for a while today at work I noticed a theme with low battery causing some strange things. So I'm charging the battery now. Could a low battery cause excess heat up on that one resistor?

The other die are Red resisted 3.3ohm 5w, and royal blue 0.5ohm 3w.


Thanks

[darth_chasm]

Hello folks.

Seeking some help trouble shooting my first build.

I jumped the pad on the PEX with solder and a bit off the trim wire of a resistor. I then have a 0.5 ohm 3w resistor on the positive off the PEX to positive on the NB board. The Foc die is white. When I take the kill key out I get the boot sound. When I turn the momentary switch on, I get non stop swing sounds and that resistor gets very hot after only about 5 seconds being on. I get no FoC activation either. After reading for a while today at work I noticed a theme with low battery causing some strange things. So I'm charging the battery now. Could a low battery cause excess heat up on that one resistor?

The other die are Red resisted 3.3ohm 5w, and royal blue 0.5ohm 3w.


Thanks

Low battery AND/OR too much current to an led are the two main causes for the constant swinging. Trying to understand better. The resistor for your FOC die is between the Nano and the PEX? If so, thats not at all correct. The resistor should be between the PEX and the die.

[KongoBongo]

Yes, I thought I saw a diagram of it on the PEX. I could not get that to look right so I just put it between the PEX and the NB. I'll re-work that now and see what happens.

Thanks.

[darth_chasm]

Give it a shot and see what happens. Your resistors seem right. The one for the red is high but I assume you're intentionally doing that for color mixing.

How hot is the resistor getting? Does it burn or is it just warm?

[KongoBongo]

Yes I was shooting for a purple. And ya it would burn if I left it on.

[darth_chasm]

Metal or carbon film? Sorry for the string questions :)

[Jay-gon Jinn]

If that resistor is getting that hot, chances are you have something wired up wrong. Pictures of your wiring would be very helpful, if you're able to get any.

[KongoBongo]

It's a carbon film from the shop. And yes I'll try and put some pictures up when I get home.

Thanks guys.

[KongoBongo]

OK! It was a wiring issue. Or, more like a soldering issue. I could not see it but the multi meter was not fooled. It was at the LEDS. The positive on White (FoC) was bridged with the Neg on the Blue. Like I said I could't see it. But I redid the joint and boom she's purring like a kitten, and no heat. On the Cree LED pads there are the positive and the negative pads. But, there are also a few other small circles that are copper colored. What are those for? I might have been on one of those.

Anyway, thanks for the help. I'll get my newbie first build pics up soon as I figure out how. =). Can't wait to start my next saber.

[darth_chasm]

Glad you got it sorted out.


On the Cree LED pads there are the positive and the negative pads. But, there are also a few other small circles that are copper colored. What are those for? I might have been on one of those.

The ones with the S's near them? Those are for wiring the leds in series.