Z axis motors underpowered?

[zhangxueyou]

I have tried that, the screw is very jumpy, i can't fix it on 1V
it jumps from 0.3V to around 4.5V in the slightest turn of the screw.

That's impossible, the max voltge between screw and gnd is around 1.5V. You must tested wrong.

[Edvash]

please - see for yourself...
https://www.youtube.com/watch?v=u9whUsBq578

[zhangxueyou]

Sorry, I can't see where you test the voltage. Are you pretty sure the voltage is tested between screw and GND? The maximum voltage is 1.5V normally.

QQ截图20150509085902.png (205.21 KiB) Viewed 9456 times

[Edvash]

obviously, this is where i measure....

[Edvash]

Hi , Two things
a) i tried to switch places with the A4988 module ,and my z axis works.... - which means the module isn't working properly
b) please read Geeetech datasheet about the maximum voltage for this component : http://www.geeetech.com/Documents/A4988-Datasheet.pdf
c) please send me another module soon, i am trying to get a response from your costumer service for couple of days now and nothing happens...

[zhangxueyou]

Yes, I know what you mean. The voltage is referring voltage. The actual voltage can be much more than 1.5V.
Our customer service will reply customers as soon as possible, they won't even delay it for a couple of days.
Could you please leave your purchase link and order number, let me check.
There are some reasons may cause A4988 become bad:
1. Wrong connection, when you plug the A4988 wrong at the beginning, reversing the connection, it may be burnt out, or even the whole mainboard be burnt out.
2. Bad cooling. We prepare a heat sink for every A4988.
3. Static electrity. It is recommended wear antistatic gloves when plugging A4988. A4988 may be dead if you don't wear antistatic glooves because of static electricity.
That's why A4988 is so easily dead, I think you have to replace a new one.

[Edvash]

Hi, first of all costumer service is sending me a new component - which is a good sign.
the second thing is that the component was already mounted to my board when i got the kit, the only thing i did was placing the heat sink
thanks for your attention
Edan