I think I have discovered a design error in most of the small T8 type CNC / engravers..
The 775 size spindle motor vent holes are obscured by the mounting plate..
3D printing to the rescue..!!!
I created a spacer block that keeps the vents free from obstruction, allowing airflow through the spindle motor... You'll need 2 x M4 mounting screws that are 5mm longer than stock..
Printed and fitted, looks like it'll do the job!!!!
Created in 123D Design, sliced with CURA
Printed in PET-G @ 100% infill
255C hot end