constant layer shift

[Roberts_Clif]

Lay shift can be caused by any mechanical part getting stuck for a short period of time.
This includes lead screws, belts, bearings and stepper motors.
All these mechanical parts can bind causing a layer shift.

Stepper motors having a low V-Ref voltage can miss steps from not having enough torque.
Belts can pickup debris causing this layer shift.
Bearing from the factory can have debris internally that caused sticking and layer shift.

[engineerusmc]

Lay shift can be caused by any mechanical part getting stuck for a short period of time.This includes lead screws, belts, bearings and stepper motors.All these mechanical parts can bind causing a layer shift. Stepper motors having a low V-Ref voltage can miss steps from not having enough torque.Belts can pickup debris causing this layer shift.Bearing from the factory can have debris internally that caused sticking and layer shift.

appreciate the feedback. what i dont understand though is how the shift only happens on one layer (not always the same layer too)