Polar Mohr 92 CS Knife does not come down

Would you happen to know about repairing these machine. I have a issue where the knife does not come down anymore. Press the two buttons and nothing happens. I have never worked on these machines before, and have not wiring diagram, I am suspecting it is a relay or something like electronic board failure ... this machine have only two PCB : main relay-connecting board and electronic board w SCR ...

 

Slip ring brushes.

 

Hi sir.
The Polar 92 CS Does not have Ring Brush
is electrical-electronic-hydraulic system
control.

 

Sorry my mistake, Did not see the CS

 

Do not worry
Everybody is doing mistakes
We are humans.