New GT2560 v3 Motherboard - Motors and Hotbed Dont Work

[macfreak84]

Hello World,

I just replaced the motherboard in my Geeetech A10 for the third time (first was DOA, second the usb stopped working after a month).

I can't get the machine to Home. None of the motors for the XYZ axis seem to work. The extruder heats up, and the LCD works, and I can read the SD card. The usb connects to the computer. I was able to flash the firmware without any issues. The bed will not heat up either. Can anyone help me figure out why my new motherboard doesn't work?

Thanks in advance,
Eliot

[macfreak84]

Ok, I've read the help section at: http://www.geeetech.com/forum/viewtopic ... 17&t=17038

My hotbed seems to work now. I still cant get ANY motors to turn. I have the A4988 motor drivers that came with the Geeetech A10. I removed all other electronics (limit switches, motors, heated bed, extruder, etc...) and measured the voltage between the potentiometer on each driver to ground. Each driver showed a 0.59v reading, except for one (the x axis) which showed 0.28v. I tried to adjust the voltage to the required 0.8-1.2v, but I was unable to adjust the voltage any higher than 0.6v on any of the drives. The driver that originally read 0.28v now reads 0.24v; I can't seem to get it any higher.

These drivers worked on the last motherboard and the machine printed fine. What's surprising to me is that the drivers are all getting the correct 5v supply they are expecting. I thought the motherboard was bad but now I dunno. Is it likely to have a problem with all drives at once??

Thanks for any help!
Eliot

[William]

It should be the motherboard IC broken.
Then it's vref is abnormal.

[macfreak84]

So you think my brand new 3rd motherboard is bad? It took me 3 weeks to get it from China....

[_kaktus_]

Hi.


The stepstick module requires two voltages to function properly.
Vcc for the control logic in your case 5V DC, and Vmot - the supply voltage for the motor. You probably have 12V DC.

Check the presence of these two voltages directly on the stepstick modules.

If the controller boards are cyclically damaged, the cause is somewhere and you need to find it.

[macfreak84]

I have 24v for Vmot on all drives. The Vcc is 5v for all drives. Is it possible I fried all my drives when the USB port on my last card died? I ordered brand new DRV8825 stepper motor drives which should arrive tomorrow. I also ordered a breadboard kit so I can test the A4988 drives that came with the machine. I'll post back when I have more info. Thanks for the help.

[William]

Hi,macfreak84
We will keep an eye on it.
Cheers

[macfreak84]

It was the stepper drivers. I replaced them with DRV8825 and modified the firmware for 1/32 stepping. Works great now! Sorry I blamed the motherboard. I have to say, at the price point for the GT2560 v3 you can't beat the features.