A success story: I've bought "Mini Motor de engranajes de Metal, MRF-300CA-14270 DC 3V/6V, 300 RPM ESPAÑA D44". It fits the place of the original motor perfectly. Only downside is that it has only 1 hole for screws (instead of many on the original motor) and that one hole is a bit offset, so I needed to drill a bit of the plastic. Also, remove a tiny plastic pin that acted as a pseudo-screw to lock the motor in place better. As for the resistors, I used 22 ohm + 27 ohm in parallel. The lid kicks a bit too much, but I decided that it's ok. Though, I think I'd suggest going with 27+27 ohm resistors. Thanks @Electronic Noob Blog for all the help!
For everybody that changed the motor but the lid still doesn’t work: I think I found the solution today! My RZ7889 Chip is fried. I switched the motor and put a variable step down converter inbetween the cables and the motor. I lowered the voltage from 14V to 5.5V so the lid doesn’t open too fast. It opened the lid but then startet glitching and didn’t close. I looked at the pcb and the RZ7889 chip looked fried, so I googled and it’s literally a dc motor direction driver. I measured the pass trough with a multimeter and it was definitely fried. Just ordered a new one, I will give an update when I’ve installed it 👍🏻
Let me know how it end up - I will be very welcome to pin up Your comment. I still deeply believe that root cause is stucked/broken motor and when it it pull to much current can lead to blowing IC - so most like Your work was not wasted. On two devices I observed that lid just open slower and slower until stop - that lead me to believe it's cause.
@Electronic Noob Blog I had a similar issue with this part so i purchased a new motor. However, when measuring the voltage at the motors connections there is constantly 13V and when the lid must operate (via sensor or button) the voltage: -drops to approx.7V for 0.5s -then back to 13v -then drops to 0v -and finally back to 13v where it remains forever. Do you have any thoughts? Thank you for any help!
Hello, I did not make any real world test - since I just swapped broken part (i'm still searching for proper replacement at 12V) - so I will be speaking of what I think instead of what I actually measured and know. Behavior You described remind me circuitry from gate opening system when it detect "over current" from motor to detect end of cycle - gate hit end - force is applied - current spike - circuitry turn motor off. Maybe micro controller is looking for current spike to turn it off - that's why it's still powered on. Main question is do You have any problems? Do You believe that motor is broken? Just connect it to 12V PSU - if it's not working than replace - most like it will eliminate issue - if this did not help then H bridge might be culprit.
@@ElectronicNoobBlog Thanks for your reply! So, I know the motor works because I have tested it connected to the wires both normally (red to red and black to black) but also opposite to verify reverse turning. When I measure the voltage on the wires from the board I get the results I mentioned. However, since there is no reverse polarity observed I agree with you it must have to do with the bridge. Could this be replaced at such a tight board? Can it be repaired somehow? Now the lid is not opening nor closing as the power on the motor is very weak, but I don't know why..
I put 1/4 watt - it's not enough (if we make calculation) but same time duty cycle is very low so I assume it's fine. I'm trying to find replacement part for 12V that don't need any resistor. I saw similar motor but with longer shaft - I'm not sure if I will be able to cut it without damage. I will be doing research.
There is separate motor on back for that motion (check my video about changing battery You can see how to access it) - mine is working fine so I did not touch it. If It fail - I will record video.
I have the same problem ... I have bought 2 Townew devices... Please inform me if you solve the problem and how... Is it possible??? This way in the video seems very difficult for me... I think I have problem also with battery because it does not keep battery power after hours of charging... Anybody to help me???
@@flavienperrais That was my second Xiaomi townew dust bin ... I will never again give money for this product... Waste of money... No local repair service. Disappointed. Maybe this is the first defective product of Xiaomi products.
I had motor that had problems just when opening - but closing work - to diagnose connect multi-meter instead of motor You should see voltage when opening and reversed polarity when closing. If it's reversing polarity - then it's fault of motor. If reversed voltage is missing i would search around H bridge.
My problem is quite opposite - my lid opens all the time without anything to trigger it - noone near, nothing above, nothing around. Can stay okay for like a minute and then wham, opens and closes a few times in a row. It isn't regular, it's chaotic and it messes me up. Imagine this can doing it at night all the time. I really can't see why though. I tried changing the location and it's still kicking.
Hi, the lid motor on my Townew is working oddly and I don’t know how to fix. I’ve taken the motor out and input 12v through it and it spins normally, even giving it just 2v it would still spins. However, when I plug it into the circuit board it will refuse to spin; I can spin the motor by hand and it would move very slowly until the status changes (on->off or off->on). I also measured the voltage on the seat, it will always measured 12v and when status changed it goes to 0 very quickly and goes back to 12v. Which is weird because theoretically it should goes to negative so the motor can spin backwards. Do you know what’s causing this and is there a way to fix?
Maybe Your revision of trash can - contain current sensing circuitry to detect when lid is open or closed. If there will be abnormality - it will false trigger. If You attach it to PSU - most like it will work fine - but that does not mean it could draw 2x rated current because of internal problem, friction or wear out contacts - and micro controller see SPIKE and assume it hit end. If I would be You - I would swap motor (it's cheap!) before digging and trying found problem on PCB. There is H bridge used for reversing polarity - that would be first thing to check if swapping motor will not resolve issue.
Measure voltage - to close lid it should be reversed. If it's not reversing it - there will be problem with "H" bridge that if I recall was made out of multiple transistors.
I think I found the solution today! The RZ7889 Chip is fried. I switched the motor, and put a variable step down converter inversen the cables and the motor. I lowered the voltage from 14V to 5.5V so the lid doesn’t open too fast. It still opened the lid and then startet glitching and didn’t close. I looked at the pcb and the RZ7889 chip looked fried, so I googled and it’s literally a dc motor direction driver. I measured the pass trough with a multimeter and it was definitely fried. Just ordered a new one, I will give an update when I’ve installed it 👍🏻
