polar 78x error 703 knife afterrun

Hi there,
I work with a polar 78x and each time i cut the error appear (703) knife afterrun and if i ignore it many the machine is blocking,I have to restart it.Can anyone help me with this problem?

 

Cause: This message is caused by an "excessive" afterrun of the knife, detected by the
computer. Although the machine can still be operated with the calculated afterrun,
the cause for this increase in afterrun ought to be analyzed and eliminated by a
service engineer. (This operating condition can be compared with the amber phase
of a traffic light).
Remedy: - Check the afterrun values in the service menu.
- Inspect main clutch (fouled by oil, brake air gap too wide, friction value of linings).
- Check magnetic clutch (iron air gap and / or brake springs).
- Check mechanical gear play.
- Bleed the gearbox
- Make sure, there is no excessive V-belt tension.
- Replace springs in brake plate (as on model 78)

 

thank's eng reda for the reply