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!

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

Thanks for putting these videos together, very useful!

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

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. :)

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

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

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.

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

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

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

Outstanding easy to understand video

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.

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

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.

Thanks a lot! Keep doing like this! :)

A great vid learned a lot. Maybe I can get my Charly (from Germany) going now. Thanks

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

great video help me sort my problem out the best .

Great vid and info. Thanks

Very nice work

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

Thanks for your tutorial lesson

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!!!

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

Helped me a lot, thanks!

Great video I appreciate brother!

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.

Good video how do we know if we have the correct mosfet

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.

Hi dude, i have bad controller, but i check 3 phases and there is no problem. So i try check resistence betwen mosfet legs and i find one with diferent resistence - shorted circuit with no resistence. you think that mosfet is broken? And when is 80V/170A i need stick with these volts and amps or can be different? how much if yes? 75V/160A? Rds same or lower and Total GATE charge same or lower? thats all what i need to know when replace this mosfet? thanks dude

Hey Friend thanks showing us , my scooter have problem at starting switch I replace one , but it not working, my friend told me the control, it’s? Can u help me please

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!

Thanks Phil did me well

Thank you! Question, which control is this?

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

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

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

obrigado por compartilhar seu conhecimento!

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?

Hello, how to remove speed limit on xiaomi himo c20? Thank you very much!

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?

great video!

Sehr gutes Video!

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

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

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

great post thankyou for that the share!

hey! how can I find the rating of the motor controller if the label removes from the motor controller mosfet? is there any way to get this number using multi meter ?

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

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.

Good stuff maynard!😁

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

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

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?

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?

Great video, very well explained. Here's what happened last week, after a heavy rain my ebike died, the display doesn't turn on anymore, so I decided to check the controller. Doing a resistance test I connected each phase wire with the negative probe while alternating the positive probe with the positive and negative of the power inlet. From each phase wire the negative gives 0 while the positive gives 18, should I conclude that all negative mosfets are blown? Please help :(

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

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

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?

what does the letters and numbers refer too on the solder side of the controller

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

Hi I am after some mosfets ru6888r There is also other numbers on it . B 89 p1926 Do these numbers matter or is it just the first one ? Kind regards daniel

Thank brother you saved me!!

Hi please can you look into my case I got about 6 blown controller I watched your video and tried to fix by testing if any mosfet is bad just like one of your video but luckily all are good So what do you think is the faulty parts . Note some of them are reading high voltages more than as it should Please guys I need a help to.

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?

Is it possible to upgrade the controller by adding mosfet? Some controller have 3 or 4 morfet per phase.

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?

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?

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...

Thank you

great vid

Thank you!

Hi Phil, really nice and helpful video. It helped me find the faulty MOSFET in my controller. However, as soon as I plug the battery connector and try to accelerate, the same MOSFET is failing... I've replaced the same twice... Any ideas?

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.

sorry mate i dont have reading on any phase with positive conector, any idea?

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.

Thank you.

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

Hey good video can you advise on whats best i recently have a fault with my scooter it powers on ok, the issue is that it won't accelerate and the brake light stays on, i have checked everything cables, battery charges ok the only thing is the controller or the motor hub i followed your video checking the misfets and can seem to find the problem ive checked the internet for a replacement but they all have different end connectors to mine are these controllers standard ? can i replace the end connectors.

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

how does this work when you have 9 mosfets? there are only 2 polarities and 3 phases, though my mosfets are in apparently banks of 3 and there are 2 the same and 1 different in each bank, i am getting shorts accross the power rails and the 3 middle mosfets are all shorted across all 3 pins, the other 6 only show continuity on the middle pin, i am assuming it is only the 3 in the middle i need to change, great info, but a bit of elaboration on if there are more than 6 mosfets (which fit into the + - of 3 phases) would be helpful, cheers

Can the mosfets overheat and be blown too?

Thank You for the video

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

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?

So, how much time to line up the long bar that locks down the mosfets? That part can be a bear to put back in.

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

Hello, I have a controller 36V with one Mofset dead exacltly like you show in your video. The mofsets inside this controller are called S68N08R-A from Si tech. I don't have another one here and I don't know where to find one to replace the dead one. But I have 12 mofsets from a destroyed overboard wich are called 100N8F6. Do you think it is possible to use one for replace the dead S68N08R mofset?

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?

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

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

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.

Great video!! Question: I have a 1000 watt Ecotric Hammer, 48 Volt, I want to use a 52 volt battery with. Is there any reason why the 48 volt controller would be damaged by this? My 48 volt battery puts out 51+ volts when it is fully charged... Why such a gray area? I don't see any 52 volt controllers for sale, but everyone is upgrading to widely available 52 volt batteries. What do you think? Thanks.

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??

Liked and subscribed. Great informative video. Any opinion on what might be causing my tsdz2 to be acting up? I know it isn't a brand you sell, but I am rather lost for what to do here. There is no torque on pedalling, and the throttle only barely allows it to move. It was working fine going up a hill, then small meandering trails down, it was functioning as well, and then when I went to go back up the hill, it turned off, and then these symptoms. The display also cuts out quick if I continue to try and use throttle. My first thought was one of the legs of power wasn't going to the motor. This is also compounded by the fact that after a few seconds of grinding slow moving, the throttle wont have function at all if let off and then pressed again, and will only regain function if the wheel is turned backwards slightly, possibly realigning something in the motor. The controller is potted, but I could probably test the mosfets, but does this seem like a mosfet issue? Thanks! see video of it here. kzfaq.info/get/bejne/iJOSgaaTsMuvaZc.html

do you sell controller for Go express folding fat bike 48v 500w brushless 4" x 2 1/2 very smoll controller