[shreifali]

Dear all,
I have my homemade cnc router machine based on hobbycnc pro board.
The machine was working perfectly and with a high precision, X and Y axis have the same setting (steps per unit, velocity and acceleratio,..).
No scale is set.
Till the problem arised: the y axis is behaving in a misterious way. Sometimes and frequently and when moving normally , it suddenly accelerates then back to normal speed. In addition , it sometimes travels the asked Distance and other times and unexpectedly travels twice the asked distance exactly.
Please may you know what might be the cause? Is it a defect in the driver or in the stepper motor? Or .....?
By the way i use mach3 for control
Best regards and thx in advance

[john-100]

Hi

if the Y axis intermittently moves exactly twice the expected distance

my first thought is to have a close look at the 3 jumpers J2.1-3 ? thats connect to the Y axis stepper IC pins 7 , 8 & 9
a poor connection could intermittently change the micro stepping setting

alternatively it could be a software issue

John

[shreifali]

Thx john for your reply.
I checked all the jumpers and connections and they were good, no short or anything else.
I also checked the software settings and were all correct.
But Could it be a virus which affects the pin dedicated to the Y axis? This problem really confuses me because it doesn't happen all the time.
Best regards,

[shreifali]

Problem solved: it was caused by a tiny corrosion at the back of the y axis settings jumpers causing it to be in full step although the jumper is set to be half step.
Brushed with a teeth brush and a little alcohol and the problem is gone.

[john-100]

Hi
good to see you have found the corroded jumper

I know from my day job there is nothing worse than “no fault found “ when investigating any reported problem

several times when a cable or some electronic equipment has been returned to the work shop because the fault was not found first time
I've taken the part to the location it was being used
to see it in the actual working conditions

John