Dude. We need more humans like this gentleman on this earth. I have a Blix Vika+ that failed on me and I called the manufacturer. Talking to them was about as useful as talking to a sack of potatoes. This dude knows exactly what he is talking about.

Thank you for the video! Helped me find and switch out a bad mosfet that went bad after a month. FWIW the replacement part for mine was IRFB 3607. Mine also was a negative mosfet but different location than in the video. Moving the mosfet back and forth until it broke off made it a lot easier to hold one leg with pliers and then heat it on the back side until it could pull out. Cleaned out the hole with Chem-wik, right stuff for the job, and in with the replacement. I was able to isolate the correct phase wire by disconnecting each phase wire in turn while rolling the bike backwards. Once the correct phase wire was disconnected, bike rolled backwards easily. Prior to that rolling backwards required more effort indicating a problem (as well as an E9 error code) Bravo - Thank you for your instructions!

Great repair guide. Justin and the team from Grin Tech are the best in the industry!

If possible, its often easier to cut the legs and remove one leg at a time. Might not save everyone a lot of time in cases like this, but its safer and easier for those unskilled or working with less than ideal tools. A weak 15W soldering iron or an oxidized tip might end up taking too long, and before you know it the traces just come right off the board. Nice video. Blown FETs is a common problem and fixing it is something most will be able to handle. Especially if they have some soldering before.

Oh yeah I have just come across GRIN channel and viewed a few of the content all worth the time so subscribed to validate my appreciation 👏

good video, the diagnostics in the beginning were helpful. I would recommend replacing the heat sink compound or at least mentioning it as this is very important in an electrically isolated heat sink. also, the wattage of your gun is important with mosfets as a lot of heat is sucked away by the large traces and the center leg. probably would have fallen out if your gun was hotter. :)

Many thanks for the nice video. The way you described the symptoms at the beginning is perfect. Now I can fix my bike thanks to you

Awesome video, didn't realize these could be opened up. Tried on my Aventon, got the end covers off but its sealed in a clear,flexible material.

This might be the problem I have with Urban Drivestyle bike. Extremely helpful video.

Super helpful video! Lots of good information for working with mosfet controllers in general. Thanks!

Excellent educational video but would have liked to see the heatsink compound replaced.

Why are all of these videos from over 2 years ago when these scooters are more popular now than ever?

thank you so much. Good Job. You just made a horrific challenge into a simple fix.

Thanks for putting these videos together, very useful!

Great video. I have the same controller as in the video and my motor just shudders and then stops when powered up. I get about 5 kohm's between battery -ve and 2 of the phase wires but only 1.8 kohm on the 3rd phase wire. Is this too low and could one of the mosfets be my problem? Resistance builds as expected on all 3 pahses against battery +ve. I've checked hall sensors and windings on motor itself and they are all good. Thanks for any help.

What causes the mosfet to fail? is a lesser amp controller more likely to fail than a bigger ah controller?

i just taken a reading on all 6 of my mosfets.. 2-6 all have a climbing voltage reading. but number 1 has a voltage spike on first contact and then begins to fall? is this the problem im having? when the system is live, its feeding 5v to all phases at the same time.. even when i apply the throttle, the voltage on all phases just sags to 0.3v and the motor makes a tiny humming sound.

I’ve only built 2 ebikes, but have already replaced 2 controllers. Now I’ll see if I can fix them!

Nice instructional content good job but I always reapply heat sink compound to new component 👍

Thank you

hello, if I give full throttle (freewheel) or put a little load on the engine, everything turns off. When I then disconnect the battery, I measure 32v on the controller side which then slowly drops. And reconnecting the battery (note a spark at the battery contact), I can start up again. could it be that my battery is too small 36v for 11max20A controller 36v direct drive motor. thank you.

I’m my case the solder actually melted and shorter the source/drain trace. So also look for melted solder sometimes mosfet can handled load but not the solder board. I packed that thing with solder to allow more current

Pretty good. I'd have applied new thermal paste, at least to the replaced MOSFET, and cleaned the flux off the board, both would add life to the controller which is, after all, the point of this exercise. Maybe you did, but you didn't mention or show either before stating it was finished and closing it back up.

Outstanding easy to understand video

Awesome video. I'm learning more and more about these ebikes. I'd rather fix my own bike rather than pay someone esle to do it . And sometimes you gotta draw a line between what to fix and what to just replace

Thanks for this. Helped me diagnose a bad mosfet in my daughter's hoverboard. Unfortunately, I'm unable to identify the mosfet, so I can't get a suitable replacement. Either way, now I know what the problem is!

I have a swagtron envy bike I think the motor is only 200 watts it has a small motor controller in it. I was having problems with it when I got a 14 amp battery at 36 volts that battery that came with it was only a 4.4 amp battery at 36 volts mine keeps cutting off the power and the display malfunctioning going crazy then I noticed the controller was getting hot is it because the battery has more amps in it how will I lower the amperage do you think I might need a new motor controller

Thanks Phil for the video. I have identified several blown Mosfets after seeing your video. I have a chinese controller with 12 Mosfets. No markings to identify them. Can you tell me what Mosfets I need, and where to get them? I have a 48V, 26amp controller.

hi,i have a problem with my ebike,battery is draining fast around 10miles range also when i put the battery on the bike it makes sparks at the connectors,i replaced the battery pack with a new one but still doesnt go more than 10miles ,im thinking it has a short but how can i test it

Thanks so much this helps I have two go out on me and the comment on the movement of the tires helped that is what caused my issue

Not sure if you will even respond but. I ran a test on the controller with a ebikes tester it showed all ok when I use my Ohm meater Ground prong to controller to 3 phase (green 9.07) (yellow 9.06) (blue 9.04) neg prob to positive controller the 3 phase wires all read 00.0 bad Controller??

When I do continuity from positive to decide which ones are positive and negative I get continuity on all 12 mosfets to battery positive and none beeps on the negative, what's that indicate?

My scooter have 12.6v but no power could this be the problem with it ?

hello guys im having an issue find the same controller was thinking to try fix it or can i use another one and put the right conectors and how do i trace wires if there diffrent colours?

My e bike mobility scooter has no brake lights and no reverse, could a bad controller be the cause.?

How can I find out what kind of electric scooter I have would it not be in marked on the scooter or the blame it all

Good mr. please my throttel not run maybe lost mosfet or short ?

I have a question about the replacemnet Mosfet. Should it be exactly matching the old. Or I can use something with in range? I have 6 mosfet controller 32V, 250W controller. Can I use 49A 55V Mosfet?

Isn't better to change all the 6 Mosfet? Even using an higher current model?

Hello I have a controller but k1 and k2 to increase speed not working, when is the problem

I've got same issue, I've established the issue is on yellow phase however my multimeter is ancient and has no beep noises... what should I be looking for on screen in terms of finding the offending mosfet? There are 5 per phase on my controller

Im trying to diagnose my nanobot d4+ 2.0 scooter. This problem does not happen in the cold morning on my first ride but happens in middle of day when it is warmer. Im in NM. What happens is both motors cut out when I'm in dual mode and when i go full throttle, and also sometimes when i try to just accelerate quickly. when it cuts out i does not come back alive by simply backing off a little on the throttle but i have to totally go back to 0 or no throttle and then the motors start if i re-engage the throttle more gently incrementing the speed. It does not happen in single mode when in just rear hub drive. When in single mode i can press the throttle fully and as quickly as I like. If I think of the thumb throttle as a clock that goes clockwise from 12 to 6. it is at the 5 when the motors cut out. It also happens if i got from 12 to 3 very very quickly. I'm pretty techy and i can replace of fix most anything but I like to diagnose first. I did have an extra thumb throttle speed controller so i did decide to replace that (because a year ago i brew out its usb power port when making a dual charger for a camera i have) but changing that speed controller had no change in the symptoms. Do you think there is a short somewhere in the system on full power or is it a hall sensor. Is it overheating and the bms cutting out? There are two controllers in the scooter with a communication wire between them, could one of the controllers be off. Both motors shut off when this happens. What tests should i run to see where the problem is? I have opened up the scooter before because I silicone sealed everything to protect from water. but actually moved to NM where there is little rain and I do not ride it in mud or water anyway. Any help appreciated.

Does anyone know where i can purchase the controller? I have a model # ST027A-ST890-800A The capacitor blew up and damaged the circuit board.

Fantastic! Very helpful. Do you have a video for checking 5v regulator transistor in the controller?

Question... I shorted out my controller by touching the positive and negative wires together on the controller. I opened it up and there is a black burn spot next to the positive and negative area inside the controller. Now my controller no longer works. What could be problem? Thank you

Boa tarde Amigo .super legal .parabéns por compartilha seus conhecimentos. Vou ver todos os seus vídeos valeu td de Bom..

great video help me sort my problem out the best .

I have a 48v Brushless Razor mx650. My problem is the motor only runs when you rotate the drive gear to a certain point. Do you think I might have a bad mosfet in my controller?

The pedal assist wiring shows positive +5V and signal wire + 4.6V. Please any help. What can I replace? The throttle works fine. Except the pedal assist not working. Please advice.

Sir i m not getting the same mosfet G067N07 n-channel what should i do

how to tell if a mosfet is bad for a treadmill? will the same apply if the treadmill motor is showing resistance if you spin the belt by hand?

Thank brother you saved me!!

Thank you for the great video. It was a big help.

How about no power on a sabvoton controller? Worked for ever and now no power. Switch wire when touched to positive battery line, minisparks but it doesn't kick sabvoton on anymore. Any where I should look first?

That speed controller looks like it has good solder lines across the board. I and wondering how can I mod a speed controller to have a good line like that. I have a Kugoo Kirin G3 electric kick scooter. And 2 speed controllers failed on me. There are burn marks at a couple mosfet solder joints. And it looks like the trace on the PCB along the mosfets is what burnt apart to a no connection.

my battery cable fell of so the kers burned anything on my controller. sadly i dont think that replacing mosfets will help if the esc just does nothing anymore, even the scooter doesnt turn on anymore. I have a functioning replacement controller but it's from a german 20 kmh m365 clone, and just the tail light flashes ... so i have to replayce broken parts but what for parts?

Hi, are all the mosfets the in the controller the same? or are there 3 negs and 3 pos? I have an ebike controller with 1 mosfet blown and all mosfets have same number on them, I cannot find these to replace, the number is ZJ7080. The controller is for a 48v 250w bike, controller says 15amp max current.

was going crazy trying to diagnose my scooter it was throttling weird i think the controller was damaged. when at full throttle it would make the motor jerky and loud and very slow. guess it wasn't the haul wires after all

Nice video interesting, just replacing a faulty mosfet, don’t know what solder they used but quite a job trying to melt the solder with very hot iron

Cool video, I think you may consider wearing a bicycle helmet with alien blinking strobes for theatrical effect

Hey thanks for the video it helped me do some troubleshooting just had a question for you so if I'm getting continuity from battery positive to two out of the three phase wires, and continuity from battery negative to the third phase wire, does that mean all 12 of the mosfets are bad? I'm also getting continuity from the positive battery connector on the board to the battery negative on the extension cable for my battery. So let's say I changed all 12 mosfets would that fix the problem or would I have to find what the problem was in the first place before I change them because they might get shorted again? It looks like some of the mosfets actually have a crack in their leg maybe they're not fully connected on the one leg there's three legs on each and about 6 out of 12 them look like they have cracks in the solder but no signs of burning or anything and the rest of the board looks okay except for one capacitor that is not swollen but it looks like it's caving in a little tiny bit. When capacitors go bad is it possible for them to cave in instead of pop up swollen? Thank you in advance for your time!!!

A Pro Great Video Thank You!!!

Hi My grandsons xiaomi has stopped working dead. The video you made has been a great help as its the first time working on these. The connector to the motor has melted so I presumed there's a short in the wiring or motor. Could you please confirm i am on the right track with that. Thank you.

What if any is the risk to replace only the 2 blown mosfets out of 6, with ones that are quite close in values V, A, Rdson?

Thank you for this video. After seen this video, I’ve found that is my problem. MOSFET. But they are 24 . It is a little bit hard for me to fix this. Can you do for me?

Thank You for the video

Hi Would you know of a replacement for these mosfets AB431A M317

Could have just unscrewed the heat sync and snipped the mosfet legs and pulled them individually. If youve got a nice chunky head on your soldering iron then its easy enough to pull it as a whole chunk. I liked the diagnostic method you used for finding the bad fet.

Nicely explained. Many thanks! PS. I own some Grin products. Great, innovative company.

I have an ebike just come in been standing in his shed 6 months, has no light on display, battery is good fully charged all wiring and connections are controller connections all good bike is only 18 months old , any pointers please ??? could be controller but all looks new condition

My controller has two wires each for the brakes(the brakes are on when i short the wires of one brake) and i want to use one of the brake's wires with relay to control with arduino is this possible ? If not what should i use?

Have an issue with my controller, once you twist the throttle then let go, the hub motor does not stop running, cruise wire is not connected nor enabled. Any diagnosis on this scenario?

Very nice work

You know what i never ask for help but... please does anyone have any ideas! I have a scooter i purchased $100 secondhand broken! Its a replica of the s11 leqismart, i got a new battery and the controller flashes red slowish speed, when the power button is pressed. Upon release nothing! No display no deeps nothing! If i hold the pwrbttn it keeps flashing aslong as i hold it😅

Thank you so much for this. I'd love to see more on electronic repairs - i have a couple chargers that need diagnosing/repair.

What will be the result if I replace 85v 150A mosfet ( k150e09ne- 18 nos) & 63v caps with 100v 200a (SSF1006 mosfet) & 100v Caps. Controller is 48v 45a...

Helped me a lot, thanks!

What if I changed the mosfet but the motor rattles like hell? Everything seems okay expect that noise.

i have a minimotors controller shorted because the accessories wire positive and negative touching, i tried replace the fuse but lcd only turn on for split second, motor also a bit weird when spinning by hand, but if i unplug the yellow wire motor turn smooth by hand. any idea how to fix it?

Hi, I have a question to ask. Today I was going to charge the battery of my 72v 40amp 8000w and once I plugged it it short circuited, are you able to tell me what is gone? So I turn on the scooter and the volt meter on the scooter is going down really really fast? Can you help me? Thank you Sir

its the yellow phase wire on power resistance test thats zero reading on negative test it starts off zero then slowly builds up to the other phase readings or up to 5kohms.i have my old 48v controller will try that soon im just waiting for some jst sm connectors to connect hall sensor back up .steve in uk

Hello maybe you can help me I have a problem on the headlight of my e-bike: it is always on but weak, when I turn off my bike, the light is a little bit stronger but still very weak, it is impossible to turn off the light unless I remove the battery. When I put the battery back, the light is again always on and weak. Is it a problem from the headlight or from the controller ? My bike is a Lankeleisi X2000+ Any help is very welcome, thank you in advance.

Great video I appreciate brother!

Good stuff maynard!😁

Thank you.

Great video, thanks. Is there a procedure for the Baserunner Baserunner_Z9 ?

Great video. My controller/motor on my kart struggles to get up to 10mph, but runs perfect after that up to 30mph. Have you ever had that type of situation? Thanks

Somehow I managed to Burn out 2 new controllers when just hooking up to the battery. I get no readings back when testing positive side, only negative side readings. And when putting the leads on both Positive direct to Negative I get nothing. Ever heard of this? New 60v battery is putting out the right current. Controller is supposed to handle up to 72v and 45amps 2000-3000 watt motor. Briefly worked but after unplugging and plugging battery to controller a few times with a decent spark at connector it fried the first one so I tried the second controller thinking it was a fluke and same thing. Ugh! Any thoughts? Hate to see this happen again. I'm going to get a spark resistor for the next one but sounds like that likely isn't the problem? Thank you

shorted yellow phase of sabvoton to positive. replaced fets but the power light wont even come on... help? will pay for a working soloution

hi i tested my controller in resistance mode like your tests and one reading is zero on red power side does that mean mosfet blown?controller not that old from alixpress 48v 1500watt on a 1000watt hub motor and 54v 18650 samsung.had throttle problem before so bought this new controller and throttle kit.lcd display lights up ok had last ride and motor died and seemed to run rough the wheel with motor in.ride before that was intermittment power.

Scooter ControlleI apologize, I have an error on the accelerator, the computer no longer works. an exclamation mark appears on the display. what is it about?rs

I need a new motor controler. Where do i get 1

Does anyone know why my 1000 watt 48 volt front hub keeps going into reverse? It'll spin properly for a bit then inexplicably reverse. PI cannot figger it out.

Any link to where I can buy these Controller Mosfets

Thanks for this great guide, the biggest problem to find the right china mosfet, in my case it is a brainpower control. DC52V (the scooter is a Speedway 4 clone + no dualtron 1x800w motor) the mosfets(to 220) have the designation: K M ..9Y ....... 19x 2452 ..... L12 .... K3475N .. Unfortunately I could not find a data sheet to find comparable replacement mosfets. does someone have a tip?

Hi I have an electric scooter I connected it to the battery indicator and it made me short-circuit the whole indicator works the lights the brake lights the horn everything except the engine you think it is

great vid

mine is shorting from possitve to yellow phase cable is the the same prossess only this time swap poss mosfet?

Hi, excelent video thanks a lot. i have a question. i have a controller that PAS works fine but throttle doesn't. i already tested throttle in another system and works fine. also made this test (fase and + or -) and it is working fine. do you know what more test can i do to the controller?

Hello Can i repair signal when it not working 0v