Initially, I built MPCNC with Nema 17 0.4A motors and everything was working fine on Ramps board with A4988 drivers. I was able to cut plywood with the cheap router from Harbor Freight (https://www.harborfreight.com/14-in-24-amp-trim-router-62659.html). But recently I have upgraded to Nema 17 1.7 A motors and my Y axis started skipping even during free move. Do you think I need TB6600 drivers or the problem may be in the different area?
Alex
Did you reset your drivers to the current current for your new steppers?
I have tried to increase current on drivers, but it did not help. Also went from 16 steps to 8 on Ramps - same. Maybe my ballbearings need fresh grease…
Also, I am connecting my steppers in parallel, maybe I should change it.
Did you do the math or just turn them up? You can very easily go overboard and get thermal shutdown. You have to set them under the max the a49 drivers can handle. I do not know what that number is, we have always used the drv’s.
Do you have a fan on your drivers? You should.
Series helps 100%.
Thank you, will check Math 
Hi alex,
i might be having the same problem. Using ramps and a4988 driver with 0.68v on x and, it skips very easily.
What was your solution?
best regards, joost