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Motor driver IC(MosFET)-Type?

MrSEG

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What is the exact type of MosFET is used for driving the Tello motors? The marking on the IC is "1C" and "W81" (s. photo)
One of them is dead on my Tello, after i´v replaced the motor, which was damaged by crash before.
Now i need to replace the IC, but i dont know, what exactly type i need.
 

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Mike Wi

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What is the exact type of MosFET is used for driving the Tello motors? The marking on the IC is "1C" and "W81" (s. photo)
One of them is dead on my Tello, after i´v replaced the motor, which was damaged by crash before.
Now i need to replace the IC, but i dont know, what exactly type i need.
What's your tello doing? I experienced a similar situation - crashed my tello & one motor was torn off. Ordered a couple new ones & did a temporary wiring. While inserting the battery the new motor suddenly startet spinning like crazy although I didn't even switched the tello on! Similar idea like you - MosFET gone 😠. I pulled the battery immediately & did cut the wires. Opened the stock tello app, did a calibration, rewired again and the motor wasn't spinning while inserting the battery 👍👍👍 - switched on & reconnected - tello's flying again. Maybe it works for you as well.
 

MrSEG

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The motor starts to spinn if i switch Tello on. But not by setting the battery. I will check you method.
I thik, i´v found the right type of MosFET. It is PMPB11EN. It has also the marking "1C". The package (SOT1220) and the other parameters seems to be rigth. I´v allready ordered a couple of it.. will see :)
 
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MrSEG

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No, in my case is the MosFET dead. It has 1,5 kOhm between S(source) and D(drain). The good one has nearly infinite resistance. The resistance D/S can be simply tested by disconnected Motors between Motors "-" pole on board and GND.
 
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ph2t

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Hey there MrSEG, great post. :) This information is what I've been looking for myself. I have yet to pull my tello apart and inspect the electronics. I have some questions that would really appreciate if you know the answers?

Are there four mosfets? Are they all nchan and on the drain side of the motor? You have confirmed what pads are the gate pads?
Would you know the drive voltage on the gate pin of the mosfets?

Also, I'm interested in trying out different mosfets that have a lower Rds(on) value. As long as they are pin-for-pin compatible and the Vgs values work for the drive voltage provided maybe other mosfets could work?

There is another mosfet from the same vendor: PMPB10XNE it has an Rds(on) of 12mOhm. Only a coupe of Ohms lower than the PMPB11EN but it might make a difference to runtime and slightly increased torque?

cheers,

ph2t.
 

MrSEG

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Hey there MrSEG, great post. :) This information is what I've been looking for myself. I have yet to pull my tello apart and inspect the electronics. I have some questions that would really appreciate if you know the answers?

Are there four mosfets? Are they all nchan and on the drain side of the motor? You have confirmed what pads are the gate pads?
Would you know the drive voltage on the gate pin of the mosfets?

Also, I'm interested in trying out different mosfets that have a lower Rds(on) value. As long as they are pin-for-pin compatible and the Vgs values work for the drive voltage provided maybe other mosfets could work?

There is another mosfet from the same vendor: PMPB10XNE it has an Rds(on) of 12mOhm. Only a coupe of Ohms lower than the PMPB11EN but it might make a difference to runtime and slightly increased torque?

cheers,

ph2t.
Hi,
Yes, there are 4 mosfets of the same type. One for each motor. The exact pinout you can see in the datasheet of the mosfet. Drain is connected to the "-" pole of the Motor.

I think the PMPB10XNE would also work. But I am not sure if the performance would increase significantly.
I think the battery would be also the bottleneck. If not, it would discharge a little faster and, of course, get hotter faster. as well as the motors. But you can try an report it :)
 

ph2t

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Thankyou mate for your replies. I am looking forward to seeing how you go with the replacement mosfets! I will do some more investigating over the following week to see what I can find out.

I've done mosfet replacements before in other RC gear, usually you find that the circuit will run cooler (lower I^2*R) on the power dissipation.
I think the motor will run OK. It's more about reducing the electrical losses in the circuit by reducing the forward drain-source resistance in the mosfet.
In the past I've found an increase in torque and slightly longer run time. This is in no means what I expect to happen for a drone as the circuits were a full h-bridge for R cars.

Still it's all about the fun trying and the hack!
Please let us know how you go!

Cheers,
ph2t.
 

MrSEG

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So, i've replaced the one defective mosfet (PMPB11EN) today. It works fine and my tello now flying again:cool: (y)like at its first day.

You can try the replacement. It will maybe work also fine ..or not. The operatig areas of the both types (PMPB10XNE/PMPB11EN) are a little bit different too. So the flying or hovering may be more instable on PMPB10XNE. But it should not be.

Let us also know if you've tried mosfet type replacement.
And good luck.

bye
MrSEG
 
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ph2t

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Awesome work :) well done! It’s great to know that there is a working replacement.
Working such small smd solder pads by hand takes some skill!
You’re right, data sheets only tell so much - you need to see the mosfet working to get a real indicator of any improvement.

May I ask please for advice on removing the pcb? Is it just the motor wires you have to de-solder? Does the video camera disconnect from the pcb or is it permanently wired? Thank you mrseg!
Cheers,
ph2t.
 

MrSEG

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I've (re)soldered it with hot air. It works well. And not so difficult. Because the mosfets are placed on the edge of pcb and are good accessible by pincette.
For removing of PCB i only desoldered the motors wires. And disconnected the cam connector.
The plug of CAM is additionally attached with silicone. That's why you should be careful here when disconnecting.
I left both antennas connected to pcb. The wires are long enough to be able to get pcb out of tello body.
I also left the antennas in the case. So that the housing of tello hangs on antenna cable on pcd during soldering. On the other side of PCB you only need to remove the cover sticker to get access to mosfets. So that is it.

bye
 
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Nanda

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I've (re)soldered it with hot air. It works well. And not so difficult. Because the mosfets are placed on the edge of pcb and are good accessible by pincette.
For removing of PCB i only desoldered the motors wires. And disconnected the cam connector.
The plug of CAM is additionally attached with silicone. That's why you should be careful here when disconnecting.
I left both antennas connected to pcb. The wires are long enough to be able to get pcb out of tello body.
I also left the antennas in the case. So that the housing of tello hangs on antenna cable on pcd during soldering. On the other side of PCB you only need to remove the cover sticker to get access to mosfets. So that is it.

bye
Hi MrSEG. I have same problem ic name 1c w7. Can u help me for samiliar ic . Thanks
 

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