Diode ID (Food Processor Switch)

[sansonet]

I have a small food processor with two speeds, but it doesn’t handle long use very well and tends to overheat. I guess I pushed it a bit too far this time because it started smoking. After letting it cool down, I tried using it again, but only the second speed is working. The motor seems fine, but I really want both speeds to work. When I opened up the switch cover, I found a component that was completely burned out—probably a diode. I want to replace it, but I'm not sure what type I need. It’s next to the switch that’s still working, but the one on the left for speed "I" isn't working at all.

[stj]

need to see the other side of the switch board to see how it's wired.

[CapLeaker]

Probably just a standard flyback diode to protect from damage due to inductive spikes when actuating the mechanical switch. That’s all that is.

[sansonet]

need to see the other side of the switch board to see how it's wired.

This is the back side, and I have marked the burned diode.

[stj]

oh shit - i think i see the (design) problem!
it only has 2 wires to the pcb right?

it's switching direct for full speed and switching through a rectifier diode for half-speed by blocking half the sinewave.
great trick with lamp bulbs, but motors are power hungry!
you need a rectifier diode preferably 1000v and as high a current as you can fit!
maybe a 1N5408

[sansonet]

oh shit - i think i see the (design) problem!
it only has 2 wires to the pcb right?

Yes, it's just two wires. Thanks for clearing that up! I'll order the diodes. Should I skip the low speed setting unless I really need to use it? I've been running it at low speed more often to keep the motor from overheating too fast.

[stj]

it's a 3A diode so it should take a lot more stress than that glass one that was probably only 1A.

[sansonet]

it's a 3A diode so it should take a lot more stress than that glass one that was probably only 1A.

I think I found the right ones on an old PC power supply. Is it okay to use them? Also, probably a dumb question, but how should the grey stripe be positioned when I solder it?

[stj]

good question.
luckily in this i dont think direction matters.

[sansonet]

good question.
luckily in this i dont think direction matters.

I just fixed it; both speeds are working now! Thank you!