The SX-S Sonosax has two fuses: one for the external power inside the mixer, the other for batteries supply, inside the compartment itself.
To change the battery power fuse, first remove the batteries compartment out of its place and remove all batteries.
On the right face of this compartment, unscrew the 2 diagonally nearest screws with the Allen key (1.5 mm) located on the left panel of the compartment and remove the cap.
The fuse is located under the two battery contacts.
Replace the defective fuse with a new identical one: 3.15 A T.
At this place a spare fuse could be attached with some adhesive tape.
Screw back the right cap, insert the batteries in the correct way and clode the left cap.