Switch broke. Help!!

[uniler]

Recently the Switch on my generic wheel stopped working. This has happened before on my other wheel and repairing it was easier because there were only 2 wires going to the Switch. This one however has 4; red, black, blue and white.I believe the red and black are from the battery and the blue and white are for the board or lights.I plan on testing the continuity on the new switch to determine which of the 4 terminals are connected while the Switch is on. I do have a question though, does polarity matter? Or does anyone know if the red goes to blue or white? Any help is welcome since i am unable to test the broken Switch and my experience is limited.

[esaj]

42 minutes ago, uniler said:

Recently the Switch on my generic wheel stopped working. This has happened before on my other wheel and repairing it was easier because there were only 2 wires going to the Switch. This one however has 4; red, black, blue and white.I believe the red and black are from the battery and the blue and white are for the board or lights.I plan on testing the continuity on the new switch to determine which of the 4 terminals are connected while the Switch is on. I do have a question though, does polarity matter? Or does anyone know if the red goes to blue or white? Any help is welcome since i am unable to test the broken Switch and my experience is limited.

My Firewheel had a power switch with an internal led-light that lit it up while powered. Based solely on this experience, and what I know about electronics:

• For the switch itself (ie. connecting two of the non-LED pins) the polarity won't matter; it just makes a connection between the two pins.
• The switch works in reverse of what I thought at first: the wheel powers on when the switch is off (ie. no connection between the two pins), and on when the switch does not connect the pins. I'd think the reason is to make sure that the wheel does not to power down if the switch fails during riding. I had the (unpleasant) joy of finding this out when I connected the batteries to a mainboard without any switch connected (the mainboard was connected to a motor, the mainboard was the wrong way around, and the wheel shot out trying to balance itself "in reverse" while built into my custom-frame):

 

• The led in the switch is not necessary for the wheel to work otherwise (although this could differ in other wheels), it's just for aesthetics / showing that the wheel is on
• On the led, the polarity of course matters; it's a LED as in Light Emitting Diode, emphasis on diode, the polarity matters, as diode will only conduct in one direction and, with sufficiently high voltage, break down in the other direction (barring more special cases, like zener-diodes or transils ). I'd expect that the circuitry on the mainboard won't give too high voltage to break it if put the wrong way around on accident; the led just wouldn't light up.

In your case, the switch could work reversely as what I described here (ie. it powers on when the pins are connected), or could even require that there's some current running through the led-portion measured on the mainboard, but I'm skeptic at least on the latter part (about the led).

[uniler]

Very informative, however i am still unsure which wires get paired. I want to be very careful not to short the battery. If I were to connect the red and black wires would the wheel turn on? Pictures attached.

 

I think the blue and white were powering the led and the others were power. So if i connect the red and black together it should turn on the wheel if i remember correctly. I am just nervous that it could short the battery if i am wrong.

[esaj]

23 minutes ago, uniler said:

Very informative, however i am still unsure which wires get paired. I want to be very careful not to short the battery. If I were to connect the red and black wires would the wheel turn on? Pictures attached.

I think the blue and white were powering the led and the others were power. So if i connect the red and black together it should turn on the wheel if i remember correctly. I am just nervous that it could short the battery if i am wrong.

If you have a multimeter (and if you don't, I strongly suggest you get one, especially if you have any suspicion you need to dig into this stuff later on, a "good enough" one won't cost more than $20):

• Try the switch with diode/continuity-mode of the meter
  • For the switch side, it should show "no connection" (infinite resistance) for the pins that are between the switch when the switch is on and keep noise + show zero voltage drop when the switch is on.
  • For the led-side, it should show "infinite" (the meter output shouldn't be able to break the LED in any circumstance) when the led pins are the wrong way around (+ and -), the other way around it should be enough to light up (at least dimly) the LED, assuming it's red or other "low voltage" color (this may depend on the meter, not all are able to light up a led)

This should already give you enough information about the switch to know the wires on that side. Usually, black and blue are the colors used for negative / ground -wires, but who knows really when it comes to these things...   Common sense would say that the wiring color on the board matches the switch, so if you know the wiring of the switch, you know the wiring of the board.

If testing on the board, you could try placing a small(ish, say 1K)-valued resistor between the wires to find out the led-side (you'd need a multimeter or at least a way to distinguis if the wheel has powered), of course the led-side won't probably be powered without the wheel turned on. I don't recall if the led inside the switch had any internal resistor, but if the mainboard already limits the led-side current, just shorting the wires together should also work, but there's a slight possibility of breaking things in case you connect the wrong wires and the board doesn't limit the currents  (thus the suggestion to use a resistor when testing).  Again, logic would say that the on/off -portion is only logic input/output (relatively high impedance), so even shorting either end on lower voltages shouldn't do much, but who knows for sure...    Sorry, I can't think of anything else right now, too drunk

 

[uniler]

Update.

I have repaired the problem and now i have s place to wire a usb charger to since the new switch does not have a light. Thank you @esaj for your help!