[Foxrena]

Today I replaced my blown blue TB6560 board with a new version (red) one. After setting up Mach3, the step motors move fine with good speed and no missing steps, but the holding torque of the motor is weaker and I can turn the motor with hand without much resistance. Before, with the blue board I was not able to do that unless I force it. I am worried because this may pose a problem if the force on table or Z-axis is stronger than the holding force. I am using a X2 mini mill by the way.

Any help would be Greatly appreciated!

Thanks,
-Mike

[SCzEngrgGroup]

If the board failed in such a way that it dumped high current through the motor, the motor may have been de-magnetized. If so, then the only fix is a new motor. Are you sure the current limit on the new board is set correctly?

Regards,
Ray L.

[wizard]

I'm not familiar with this board but I wonder if you have something configured differently. Specifically there may be a setting to reduce idle current. As has been mentioned a bad motor is a possibility, but if you are getting the same acceleration and top speed that probably isn't the issue.

In situations like this I always recheck the settings for the driver. In the old days that meant pots to twist. The various single chip motor drivers have many settings that have to be configured properly. Hopefully the problem isn't hard coded.

[Foxrena]

Thanks guys for your kind replies.
I did more tests with different DIP settings and found that the decay rate with this new board is much faster than the old model. Before I used to use the fastest decay setting and it performs well at very low speed. Now with the new board I have to use the lowest decay rate to get the low speed performance required, and it gives bad resonance through the motor and ballscrews. Still the motor holding torque is not as good as before, and I have tried all the DIP settings.
It may be forgivable since the steps are accurate and I can get good positioning.