Stepper L and Stepper R Dead


#1

Hi,
Yesterday I was working with Dobot, all good, making him do some basic movement with Teach and Playback to see if he could repeat the commands many times. It all worked good.
This morning, when I powered it up, both the Stepper L and the Stepper R seem to be dead.
Usually after power up, the motors keep it in a fixed position, but now I power it up and the only motor that is actually doing something is the Stepper Rot.
Unless I hold it it just falls to the table. I try to command it to move the joints and the Servos are working and the Stepper Rot is also responding, but the Stepper L&R both ignore me.
Seeing this I’m starting to worry that they are dead. I hope that is not the case.
Anything I can do to try and get them working again? Any test I could do to make sure they are actually broken? (Like some tests with a multimeter or something?)


#2

Check the driver board on the control board. You can plug the driver board of the stepper Rot to the stepper L or stepper R socket, see if the stepper will move or not. If they move then the driver board might be dead.


#3

I was just going to write about that.
I tried and indeed, what is dead is the driver boards.
Any way I can fix them? Any reason why they would just die like this?
If I cannot repair them, could you guys send me more?


#4

I think you can help me to measure the voltage between the trim pot and GND, see if it is proper or not. Adjust it to about 0.5-0.8V and see if it works. The trim pot is on the driver board.


#5

Sorry I just want to make sure, which pin should I make sure has 0.5-0.8V on it?
The trim pot has 4 pins so not sure exactly which of them I should check?


#6

Just put the red probe on the trimpot and the black one on the GND and you’ll get the voltage. Then you can rotate the trimpot to adjust the voltage.


#7

I checked the voltage of all pins, in all boards looks the same.
If you look at the board placed so that you can read the letters of the chip (4988ET)
On the upper right pin there is about 0.8V, on the left there is about 0.4.
There are very small differences between the boards so I guess the potentiometer is correct.


#8

OK doing that I get 0.4V in the one that works, and 0.42 and 0.43 in the other 2. I guess that shouldn’t make any difference.
Anything else I could test?


#9

That’s werid…But if like you said, you can make the other motors working using the Rot driver, then the driver boards are dead, not the mainboard, just need to change the driver boards. Tell me your mailbox and we’ll contact you later to send you the new driver boards.


#10

Ok, I think that the problems are the driver boards too.
Please contact me to marti.salvador@kal.com


#11

Thanks and sorry for you trouble! We’ll contact you as soon as possible.


#12

Thank for the help, I’m already in contact with Support and we will arrange to get me some new Drivers.


#13

Also the AC/DC Adapter (GMY-1260W-5F) stopped working as well…
Could you guys contact me again to see if we can do something about this?
Thank you.


#14

I opened the Power Supply to see if I could fix it myself and this is what I found inside. This is by far the worst I’ve ever seen.
Also when looking for the same model GMY-1260W-5F I simply cannot find anything online about it. I found a similar model, the GMY-1260W-5X.
Can you explain this? And please provide another Power Supply as soon as possible, because now I cannot use Dobot.
Thanks


#15

Sorry for the trouble! Believe me, you’re the first one that has a bad driver board and a bad power supply, really weird. I’l have the customer support contact you asap.


#16

We’ve already send you a power supply, it’s not the same type but it will compatible with your dobot, don’t worry.


#17

Yes well the Drivers can be just bad luck I guess.
But this Power Supply is very poor quality you guys should think about using some other model!
Thanks for sending it to me, could you please ask customer support to send me any tracking number they might have, for both the drivers and the power supply?
Or give me some Estimated time of arrival?
Thank you


#18

We order the drivers and power supply from ebay for you, the delivery info are as follows.


#19

Ok thank you for that. I hope they get here as soon as possible.


#20

Hi…as suggested above you can make the other motors working using the Rot driver, then the driver boards are dead, not the mainboard, just need to change the driver boards. Tell me your mailbox and we’ll contact you later to send you the new driver boards.

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