nema42 steppers loosing steps please need advice

[onkart]

hi this is my first cnc build hoping for some assistance . I have retrofitted a older cnc base replaced ball screws and added a 24" z , there is no backlash and mechanical has been ruled out, bought (eBay) the nema42 with the 4120oz , stepper driver/ power supply dq2722m set at 220volt , driver is set at 1000 (micro steps I believe ? dip switches)step per is set at 4000 and calibrated in x and y , tpi 2.5 ball screw , accel is 22 and velocity is 111, dir 5 pulse 5 , z is a bit different, computer is 2.8 processor 1.25gb ram dell desktop , kernel is set to 60,000 mach3 is licenced, I am at these settings as I went through just about all of them and this seems to be the best combination , i have slowed it down etc., though I am still missing steps in all axis, hoping someone has a solution as I have spent a couple of weeks and seems to be at a standstill as far as improvements on the missing steps, i have read a smooth stepper board may be a fix, any advice ? if so where and what to purchase, thank you in advance for your assistance, Perry

[onkart]

update, at this time through many hour invested, it appears as though we have 2 bad driver boards as well as 2 bad motors, i will request some sort of warranty (good luck i know)

[James Newton]

Consider buying a quality driver like a Linistepper or a Geckdrive.