Z Motors Jerking ? - see video

[156801]

Hi,
new to 3d printing and worked my way through a few problem but have come across a new one.

All of a sudden both z motors have started to stop and start. This can happen when moving up or down.

I would not say they are jerking as you can see in the video they stop and start both motors at the same time and there is a clunking noise. Happens when disconnected or connected to a laptop. Tried reloading old firmware with no luck.

When both motors are stationary they made a slight grinding noise and if you turn the rods with power on they feel different to turning the x axis.

Video link https://drive.google.com/open?id=1DkOPE ... gPNVXEIaVp

Printer is a Geeetech I3 Pro B W with GT2560 board.

Any thought would be great full.

Robert

[Gingko]

Hi
I think you can check the voltage of A4988 of Z-axis, increase it to 1.0V.

The left and right sides of the Z-axis should be at exactly the same height.
refer to:viewtopic.php?f=22&t=16917

For more suggestions, you can check this post:
http://geeetech.com/forum/viewtopic.php?f=82&t=60931

[156801]

Thanks for the reply.

I had read those posts, mainly mechanical problems. The problems happen even when the threaded rods are NOT connected to the motors.

I was thinking about the power supply and adjusting it. I have not because both motors both start and stop at the same. Time so both motor have the identical problem .

I would assume that a reduced voltage would only affect one motor?

I will check the voltage to be sure.

My thoughts is it a software issue as the motor were running fine and then just played up. I think the y motor also reversed but is now ok. Fixed itself some how.

[156801]

Adjusted the voltage on the stepper and so far so good.

Thanks for the help.