View Full Version : How to fix the missing capacitor on MR03 board?

2011.02.17, 02:25 PM

I'd like to know how to fix this board with the missing capacitor(between the motor wires). What can I put back on there from Radio shack, etc...?

2011.02.17, 02:28 PM
sai, i think brandon has a thread going on the very same subject which may have the info you need. i don't recall what the thread title was though.

2011.02.17, 04:15 PM
Sai, I have a board that is missing that capacitor, if you want it to test with, or steal a cap off of a different location to fix this board (Im pretty sure I saw at least one that looked the same on the opposite side)... let me know...

2011.02.17, 04:39 PM
The stock size capacitor is extremly difficult to solder. I have some extras myself but I want to find a larger and easier replacement.

2011.02.17, 06:16 PM
It looks like an 0603, probably .1 uf.
It's kind of redundant because there is another at the other end of the motor wires.
The cap you are missing simply goes from one motor wire to the other, so you could get some through hole ones from Radio shack and solder it into the holes.

You can also salvage one from an old motor, look for one that says 104 on it.

2011.02.17, 06:34 PM
hmm... now how'd that happen?

2011.02.17, 09:37 PM
If you don't have SMT soldering equipment I highly un-recommend even trying. You can get away soldering FETs because they're big and have leads on them, but SMT capacitors (and everything on the board actually) really need to be either hot-air soldered or reflow soldered.

Like I-lap said, just solder any small capacitor (not an electrolytic) that you can fit around your friction setup between the motor pads. It would be even easier to solder a cap to the bits of exposed wire of your motor leads. Anything from 1,000 pico to 100 nano should be fine.

2011.02.18, 12:38 PM
I have lost that capacitor on my MR-03 a few weeks ago; I since ran two HFAY and I did not notice any change or glitching with the car... What is the purpose of that cap?

2011.02.18, 12:57 PM
2.4 systems are inherently less susceptible to motor noise, and there are already some caps on the motor.

Rather than trying to replace the on board cap, putting it across the motor terminals on the actual motor is actually a better idea anyway. The cap should be as close to the source of noise as possible.