The low power (warm) circuit is on constantly so long as the device is plugged in. The larger heating unit only works when the pressure/magnet circuit is closed. The alloy in the "weight sense button" has a curie temperature JUST above that of boiling water. Water CANNOT be heated such that its temperature increases above 100 degrees celcius, no matter how much heat is applied. That will only make the water boil away faster (there is specific heat capacity that relates to the amount of energy required to convert matter from one state into another, so more energy into the system means converting that state faster, not increasing the temperature beyond that which it can exist in that state. The water cannot go above it's boiling temperature, but the RICE CAN. That thermal switch will stay active (the magnetic properties of the alloy disk remain) so long as the temperature doesn't exceed the curie temperature of the disk. When the water is absorbed into the rice, it is assumed to be cooked (presuming correct water to rice ratio, the water will only absorb when heated to around boiling for a given amount of time-enough to typically cook the rice). Once the water is all absorbed into the rice (and it is coincidentally cooked), the RICE will begin to heat up with additional energy input as the rice will probably continue to heat up until it combusts. When the rice hits that curie point just above boiling, it temporarily loses its magnetic properties. The spring that is trying to force it away is now above to disengage the 'dongle" because the magnet is no longer countering the effect, so the circuit opens-leaving only the "heating" element engaged. The pressure portion of the design is for safety, in case the bowl is removed during cooking-the circuit will automatically kick off and only the warming element will remain active-less chance of a fire. Simple and elegant engineering.

@TheNormalUniverse

3 жыл бұрын

Thanks for the rundown. Yup I agree with all of this.

Thanks to you, I fixed my rice cooker! The problem was as simple as the metal bowl going concave over time and not pushing down on the magnet far enough for the circuit to latch.

@TheNormalUniverse

4 жыл бұрын

Joel Mades wow that’s awesome! Nice job

Thanks for this investigation. The magnet/curie point makes perfect sense and had me stumped too. I had a thermal fuse go bad on mine and I went to fix it. The thermal fuse was rated for 141C, so thats what I replaced it with. I was under the understanding that the cooker shuts off when it goes above 100C, so I figured that if the fuse got to 141C, then things went wrong so it kills itself. After the repair, I felt like the rice was getting slightly overdone, but it was working properly. I was afraid that maybe my fuse repair had something to do with it, but of course that would make no sense since the fuse is a safety device of last resort, and unrelated to the regular operation. I measured the temp of the heating element at shut-off, looking to confirm that it shuts off in-time at just over 100C. The heating element got to 170C, which seemed way too high!. I was thinking that maybe there was a bi-metallic strip switch inside the center button, and maybe that was no longer calibrated right due to the overheat condition that damaged my thermal fuse. So anyway, i guess maybe my overheat situation could have altered the state of the magnet or the metal, but seems unlikely.

Love the "repairdown" name. These are so fun to watch!

@TheNormalUniverse

8 жыл бұрын

Thanks Phil! I want to make it a thing like mythbusters. Sometimes the device will be repaired and sometimes recycled. I need a little animation to play at the end once the verdict is payed down.

There's also a thermal fuse in the circuit that opens when the cooker gets too hot. It's a little hard to find because it's tiny and fits inside one of the wire insulator tubes. Replacing that fuse would have very likely fixed the cooker.

@TheNormalUniverse

3 жыл бұрын

I think this is probably the right answer!

You are really a genius man. You made me crystal clear how RC works. I hope other videos related to other electronics too. Thank You man.

The thermodisc in the center of the cooker is a klixon. It physically knocks the pot out of cook mode when it reachs doneness temps. .its always on warm when plugged in.

That was awesome. Great concept and edits.

@TheNormalUniverse

8 жыл бұрын

Thanks Craig!

Correction at 4 minutes. The silver card type device is not another heating element but a thermostat for keeping the food warm. So all thermostats work with temperature. This one will keep the food warm by switching on the heating element and when it gets to the set level it switches off the element similar to how an iron works when ironing clothes. This is my understanding. A good take away from your video is the tear down and I did learn about the magnetic switch when you put it in the fire, something the other videos did not show. Good one.

@TheNormalUniverse

5 жыл бұрын

Thanks for watching! I disagree. That silver card shaped thing is definitely another heating element. If it were some type of temperature sensor that turned the main heater on and off, there is no mechanism in the circuitry to turn on and off the main heater using a sensor.

@ahmedtwahir

5 жыл бұрын

A quick search on google, ebay or aliexpress using "rice cooker thermostat" will show you the same device. Check the warming circuit.

@ahmedtwahir

5 жыл бұрын

You're right, on another site the same device is called a heater plate, according to some of the circuits I believe the cooker automatically goes into warming when plugged in then cooking mode when the switch is turned on.

@DraRed73

5 жыл бұрын

I don't think it is a heating element. I just pulled one apart and the location and size of the device would not be suitable for heating. My guess is that it is a temperature sensitive resister. Current flows through to the element to heat the bowl but as the bowl heats up, resistance would increase and thus keep the temperature in check.

Reverse-engineering a rice cooker! Thanks, I can finally understand how it works

Thank you ! Always wondered how it works !

@TheNormalUniverse

5 жыл бұрын

Haha thanks. This is one of my weirder videos but people are actually searching for it.

My almost new pot works but won't switch to the warm only position. Not too safe. I will dismantle it now. Thanks for the good info.

Cool-or hot, I guess haha! I have a couple questions: is it the magnet or is it the other metal which loses its magnetism due to the heat? Also, why did you declare the rice cooker totalled? Did you just determine it wasn't worth diagnosing further, or did you identify what the exact problem was and didn't think it was worth repairing? Was the teardown itself destructive? To be clear, I'm not criticizing! I've performed some electronics surgeries that turned into autopsies/organ donations :-P

@TheNormalUniverse

3 жыл бұрын

No worries! I didn’t get any negative vibes from your questions at all. It is the magnet that loses its magnetism above the “Curie temperature” for that material. Every magnet material has a different curie temp. This one has likely been engineered to be slightly higher than the boiling temp of water, so it triggers after the water boils off. I don’t remember why I decided to toss the rice cooker. Most likely because the fix didn’t seem easy and buying a new cooker was just $20, so I wanted to move on. In retrospect, I would double check to see if the pot in the rice cooker was properly touching the magnet trigger. If the pot were dented and there was an air gap between trigger and pot; then the trigger would get hot really fast and turn off before the water evaporates. I think that matches the symptoms I saw. At the time I thought there was something wrong with the magnet that shifted its curie temperature. In retrospect the dent hypothesis seems more likely than a shift in the magnet material properties.

Good video - was disappointed to see you stopped making them 10 months ago. Regardless, I still subscribed - I hope to see more content soon!

@normaluniverse2804

6 жыл бұрын

Joseph Grasser hey thanks for the vote of confidence! I just got swamped with work. Trying to get my balance back in order, really want to start making vids again.

For this model check the bottom of the cooking fan. If you noticed when the pan was new it was a little concave and may get deformed through time.

My guess is that the cooker has been disengaging too early because of degradation of the magnet or the spring.

@TheNormalUniverse

8 жыл бұрын

I agree. I was thinking if the spring got weaker it would trigger at a higher temp and overcook the rice, but if the magnet got weaker it would trigger at a lower temp, so I think it's the magnet somehow. That's why I gave up, because magnets, how do they work?

@HVeTz

8 жыл бұрын

You might be able to find a replacement part but it's probably not worth the effort.

Can you explain the materiality of the thing that senses the weight and temperature?

Hi i want to redirect that center spring part to use as a cooking stove how i can do that?

Nice

hi , how to repair aroma rice cooker, i was accidentally plugged in on 220 voltz. instead on 110v . is it possible to repair it? hope you can help me

@TheNormalUniverse

7 жыл бұрын

Sure, can you describe everything you can about how it's broken? What happened the moment it broke? What happens when you plug it in? Discoloration?

Can I solder (or connect to one of the screws) the ground pin plug to the metallic part of the heating coil?

@TheNormalUniverse

Жыл бұрын

sorry I don't know the answer to that. Be careful around mains voltage please!

What is a "rice cooker thermal insulator film" for? Google only returns items from aliexpress but I can't find an explanation what it does.

@TheNormalUniverse

5 жыл бұрын

sorry never heard of that

@markoli2455

5 жыл бұрын

Number 6 in this photo: i.imgur.com/J53s0Ur.jpg Advertised on Aliexpress: www.aliexpress.com/item/Free-Shipping-electric-rice-cooker-thermal-insulation-film-rice-cooker-isothermal-rice-cooker-parts-rice-cooker/32321903572.html

@markoli2455

5 жыл бұрын

I watched the entire video and at 3:58 you mentioned it's a heater. Still doesn't make sense why it's sold as thermal insulator. And also why it's mounted between the inner and outer shell if it's a heater, coz that would warm the outer shell instead of the aluminum pot.

it was a mystery before u told me than ... thanks a lot sir.... it was really helpful

@TheNormalUniverse

7 жыл бұрын

Thanks safiq, going to fix some headphones soon!

@ShafiqIslam

7 жыл бұрын

//will appreciate

the only knowledge that I learned here is magnet abilities to magnetize will gone because of intense heat

i guess the small element is connected series as a resistor to main heating element

@TheNormalUniverse

4 жыл бұрын

The small element is always on while the cooker is plugged in. If the small element were wired in series with the main heating element then the small element would turn off an on when the main element does. So the main element and small element are wired in parallel. THEN, only the main element has that magnetic switch wired in series to control it. (sorry if this is hard to understand without a picture)

@khusenpradhan3386

4 жыл бұрын

if its so i find it really helpful thanks for your reply :)

How to repair heating element

My RC working fine but the next day, rice over heat turned brown, anyone could help? I guess keep warm thermostat didn't cut out in certance temperature, where to buy keep warm thermostat? Is it look like silver card type? Thanks

@TheNormalUniverse

4 жыл бұрын

Sorry I don't know. Good luck!

I have Philips rice cooker ,all works well but rice gets burn most of time , can anyone help me tks

My RC working fine but the next day, rice over heat turned brown, anyone could help? Thanks

I always just assumed it was Chinese magic

My rice cooker take much time to getting hot and take much time to cook rice

Yo..it was working from beginning...you fucking destroyed it.."too bad I couldn't fix it" ..next time out it together and donate it

This is a nice video for fix rice issue, Also here you will see fix magnate and switch kzread.info/dash/bejne/gXqoq8FtYqXVcaw.html

Quitter

@TheNormalUniverse

3 жыл бұрын

haha you're not wrong

nice video. have a good one. add some more personality and some video work for more hits

@TheNormalUniverse

7 жыл бұрын

Sam tron haha personality is the hardest part

@CaptainManic2010

7 жыл бұрын

for some people mate. You're an analytical. Be proud. But even analytical people...engineers...scientists...general smarty pants...can learn to express. We can see bits of who you are...and it's a cool show...but for you to share more of you? with boundaries...will get more people to like you and watch.