Why does kenwood Kmix not work at times when turned On speed switch?

Why my Kenwood Kmx50 Kmix does not work at times when turned On the speed switch? At times it works but sometimes it just won't start. Some say that you need to wait for a few seconds and then start but it still does not work.

crwdns2893858:0crwdne2893858:0 crwdns2893862:0crwdne2893862:0

crwdns2894050:0crwdne2894050:0

crwdns2889612:0crwdne2889612:0 2

crwdns2893872:0crwdne2893872:0:

It looks like a intermediate fault.

crwdns2893770:0crwdnd2893770:0crwdne2893770:0

crwdns2892346:0crwdne2892346:0