Delta stepper movement problems

I am building a Kossel Maxi – and just got the RAMPS board wired up and am doing my initial testing and calibrations (Marlin FW).

Found two odd behaviors that I’m seeking advice on:

1) Movement in Z up or down works fine using the control wheel in Repetier Host. If the printer is homed, hitting “home” again will do the little three-step re-home dance perfectly. However, if the printer’s z height is below the endstops, there is a buzzing as it tries to work its way back to home. My guess is my stepper drivers aren’t adjusted properly yet. We’ve set them at .500, .400, and .300 v with equal results. I’ll keep iterating, but if anyone has other suggestions, I’m all ears.
2) There is no movement in –Y or –X , but +Y and +X work fine. So, if the effector head is sitting at 0,0, it can move to 90,90, but then it cannot move back to 0,0. Nor, can it move to -90,-90.

Any thoughts or suggestions are welcome.

Fixed problem 1 with adjustment to speed in firmware.

Problem 2 is still there... (correction though:2) There is no movement in +Y or +X , but -Y and -X movements work fine. So, if the effector head is sitting at 0,0, it can move to -90,-90, and back to 0,0. But it cannot move to -90,-90. (or 0,-90 or -90,0)

Anyone?

I have no experience with Repetier but just my 2 cents worth which may point you in the right direction

I recall that Marlin wont allow positive axis motion until it has seen its endstops.

I had something similar and if i recall it was because i hadn't checked "center of bed is 0.0" in Simplify3D. Excuse my memory as i am wallowing in my own set of set up issues.

Good luck

Turns out it was printer settings off in Repetier