Geeetech

no, i have instead switched to 0.9 degree stepper motors

Yes, i want do drive them 1/32 step with all jumpers ON but i have also tested different combinations down to 1/2 step....same issue

I have Pro C printer with GT2560 board and A4988 stepper motor drivers. I order to lower printer noise i swapped them with DRV8825 drivers that i got from geeetech. I have adjusted current limits and steps per mm in the firmware.
The motors are turning but i can now hear horrible high pitched noise ...

the manual is correct
http://www.geeetech.com/Documents/pro%20C%20building_instruction%20.pdf

I actually already got the STL file from sherry.li@geeetech.cn
The bracket that came with my printer has melted, it may have been made with PLA. I printed some new ones with ABS and nylon and they work ...

I have tested it and can confirm that 80 steps is much better value for Pro C. The tolerances is more precise now. Geeetech may consider to change the value to the correct one for GT2 belts next time they update firmware.

the in the Pro C (marlin) firmware that i have downloaded from a link in the forun it states:

#define DEFAULT_AXIS_STEPS_PER_UNIT {78.74,78.74,2560,95} // MXL, Z M8=1.25, MK8

MXL has 2.032mm pitch and GT2 is 2mm which makes 80.0 steps (1/16)

If my printer has GT2 belts that the 78.74 is wrong ...

I looks like it called "belt bracket" in the manual

There only old parts for the Prusa i3 pro C
I need to print a new X belt tensioner for my printer. It sits behind the MK8 carriage.