Huxley Build: Y Axis Missing or Adding Steps

Things have gone pretty well so far in building my Huxley kit but now I am on to the first print and am stuck.

There is a problem with the Y axis not stepping correctly.
After 2 to 3 layers the Y seems to lose or gain a couple of steps.
Here is a photo showing the effect


I decided to check it by just re-positioning the Y axis from the printer interface and sure enough at high speed the stepper misses steps. Slowing it down seems to cure the problem. So I decided to plug it into the X axis plug on the control board and it does not miss steps at any speed. This suggests that the Y stepper and its wiring are OK.
I have adjusted the voltage setting on the Sanguinololu board in the hope that a different voltage (from the 0.4v it is set to) will cure the problem. All to no avail. I also noticed that the motor runs much smoother and quieter when fitted to the X driver than it does when fitted to its own Y driver.

So I can only conclude that there must be something wrong with the driver for the Y stepper motor.

Any suggestions as to what else I could check? Has anyone encountered a similar problem and discovered a cure?

Thanks

Will

Try swapping the drivers for X and Y, and see if the problem transfers to the X axis. If so, and increasing the pot doesn't help, you may have a bad driver. Luckily they are easy to replace and not expensive.

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Thank you for that Cameron. I swapped just the driver pcbs (didn't realise that they would just unplug) and sure enough the fault transferred to the X axis. Also the rough sounding steps transferred with it whereas the Y axis is now very smooth.

Here is a picture of another test print which confirms



So I'd better go and buy another one.

Many thanks

Will