Fixing a broken popcorn machine

nsz
2018-08-30T19:52:23Z

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So we have had this popcorn machine for ages and just recently it completely stopped working. Being a fan of bigclive on youtube I though why not try fix it and maybe get a sense of how it works.

The guts

The insides honestly are pretty underwhelming - both the impeller and heating elements are quite small considering it only takes a few minutes to make a bowl of popcorn.

Circuit board and Another shot

Considering how few components there it was not too time-consuming to draw up a diagram. Please excuse the crude drawing.

From what I can tell it uses a bridge rectifier with a some caps to convert DC and even out the signal - and what looks like two resistors to further drop the voltage to the motor, maybe two offered better cooling? idk why they didn't use one. It's also kind of interesting how they used two separate coils for the heating with one of them in series with the motor, that will drop the voltage right?

They also have overheating protection here, with a an sefuse and a thermo switch, it actually has the piece of metal and a contact that will bend away when it's hot, I've only seen these in a textbook. Not sure why there are two types of thermo fuses?

The fault

Finding the fault ended up being quite easy, the main heating coil that comes off blue wire had melted. A piece of corn, oil, bits of salt or a mixture had found their way in and somehow melted the wire in multiple places. It cut the circuit so not even the motor was working which was my initial though when it stopped. I wound some solid core wire around the two ends, hopefully it will not unfurl or melt in the heat.

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