Author Topic: problem with eleksmaker a3  (Read 133 times)

Entargo

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problem with eleksmaker a3
« on: November 29, 2019, 05:34:01 PM »
Hello, I have a new eleksmaker a3 pro?  This machine has worked perfectly for over a month now.  Im about at my wits end!  I have tried everything i can think of. Ive cleaned the tracks, replaced the motors, with new ones.   Changed the firmware to different versions switched the motors around but the problem persist.  The motors are sticking and humming at certain areas of the gantry.  This has only started happening recently. I checked the belts and they are fine.  I've loosened the rollers everything.  I took one of the motors off and it spins but then stops or shakes and gets stuck until i move it by hand.  I've read that this could be a voltage issue, could this be the problem and if so how can i change the voltage to make it work? Oh and i have the full version of T2

ggallant571

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Re: problem with eleksmaker a3
« Reply #1 on: November 29, 2019, 07:45:24 PM »
There are stepper motor driver boards/chips such as the A4988 that convert the low power CPU STEP signals into high power motor drive signals. They have a current limit adjustment trim pot. If the current limit is to low the motors will appear to stall under load. If it is too high things will overheat and also lose steps. For the A4988 the typical value is 0.45V per motor. You measure the voltage from the case of the trim pot to a GND. Some people clip the test probe to the screw driver while adjusting. Quite small rotational distance can have a large change in voltage. I run mine slightly hot as I do not want any small imperfections in the wheels and rails to cause problems,

A typical etcher has 2 motors on the Y and and single on the X. If they were working OK and then you swapped the drivers the X would now be hot and the Y under-powered.

Other common problem:
1. Broken wire or connector
2. Bad wheel bearing
3. Misaligned axle housing
4. Bad power supply.

SARCASM - Just one more service we offer here.

Zax

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Re: problem with eleksmaker a3
« Reply #2 on: November 30, 2019, 05:46:27 AM »
If you've been moving the machine manually (by hand) chances are you've damaged the stepper driver. The motors are pretty robust so unlikely to fail however moving them manually creates back-EMF (motors act as generators) and the drivers have very little resistance to the current flowing in reverse and fail usually causing juddering of the motor.

Entargo

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Re: problem with eleksmaker a3
« Reply #3 on: December 01, 2019, 12:07:48 PM »
Zax I think maybe you are right.  Changing the voltage made it worse, so I got another board on order.

Zax

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Re: problem with eleksmaker a3
« Reply #4 on: December 01, 2019, 01:15:38 PM »
A4988 stepper drivers are very cheap, under $2 each (the DRV8825 are similarly priced and drop in compatible).