Possible cause 1: The blade set is not adjusted correctly. If necessary, re-adjust the cutting pressure. To do this, tighten the knurled screw so much that the upper cutting blade can be pushed back and forth with medium pressure between thumb and forefinger.
Or adjust with the Torqui GT142.
Possible cause 2: There is hair and/or dirt between the blades. Disassemble the blade set and clean all parts.
Possible cause 3: The blade set wobbles and vibrates strongly when switching on the clipper. Check, if the dovetail (blade holder) is loose. Tighten the fastening screws. Check whether the dovetail is worn. If so, a service is due.
Possible cause 4: The blade set is not properly engaged on the eccentric drive/lever. Switch off the machine and remove the blade set. Push the blade set halfway onto the dovetail, switch on the machine with the machine running, push the blade set completely on while pressing the lever at the side.