Stepper motor - loss of steps

setp stepgen.0.steplen 1
setp stepgen.0.stepspace 0
setp stepgen.0.dirhold 44000
setp stepgen.0.dirsetup 44000

Your DIR setup and hold times of 44000 are probably OK but steplen and stepspace should be set to something like 10000 or even 20000. These numbers are nanoseconds so 10000 would give a value of 10 uSec.

The OP is using the "reset" mode so step time is set by the reset time here:

setp parport.0.reset-time 5000

(U32) parport.<portnum>.reset-time -- The time (in nanoseconds) between a pin is set by write and reset by the reset function if it is enabled.

Interesting. I did not realize it worked like that.

5microstepping is also a steplos killer

better to use externel timingbelts for balscrew it is 20/25 teeth so 1,25 gear
that brings in 0,01mm per step at halfstepping
and gets a full speed full torque running mashine

the
color code is most
A+ RED
A- Blue
B+ Green
B- Black

if you change like most Black /green it will likly loos at higher speed at around 100RPM of the stepper

persei8 wrote: setp stepgen.0.steplen 1
setp stepgen.0.stepspace 0
setp stepgen.0.dirhold 44000
setp stepgen.0.dirsetup 44000

Your DIR setup and hold times of 44000 are probably OK but steplen and stepspace should be set to something like 10000 or even 20000. These numbers are nanoseconds so 10000 would give a value of 10 uSec.

Uhmmmm.....I'm getting a little bit lost
Ok, I understand the change of values for stepspace and steplen (I'll change to 15000, in the middle, according to your suggestion)

pl7i92 wrote: 5microstepping is also a steplos killer

better to use externel timingbelts for balscrew it is 20/25 teeth so 1,25 gear
that brings in 0,01mm per step at halfstepping
and gets a full speed full torque running mashine

the
color code is most
A+ RED
A- Blue
B+ Green
B- Black

if you change like most Black /green it will likly loos at higher speed at around 100RPM of the stepper

But I'm a little bit confused about this, if you can kindly explain me the thing....

BTW, as suggested by persei8, I'm planning (wife and job allowing - and weather too, my garage is hot like an oven) to overhaul the mechanics and the wiring too, hopefully in the next days

Past week I checked the structure, then this weekend I checked the electronics and stepper.
When disassembled the steppers, I found the X coupler broken.....
Maybe an invisible crack (factory?) wich eventually gave up.
Well, I'll go on with the review of all (mechanics and electronics) and see what will go on.