My Kenwood mixer , on heavy duty, is sometimes speeding up and slowing down,...'. Without touching . What could be the reasontype Kenwood Chef 1500W

SOURCE: kenwood chef excel attaching blender

http://www.kitchenmanuals.com/manuals/mfg/kenwood/km300_km400_km600_km800.html

hers the manaul for u rate me as fix ya ok its a pdf file also thx nick use adobe reader to view it 43 pages thx agian for using fix ya

SOURCE: Blakeslee (Kenwood) A717 mixer speed control

I had the same problem. Had to strip the machine down to get to the motor. On the top is a moving plate with various capacitors etc mounted. On the front side there was a Capacitor (At least I think it was) with the wire broken.
I resoldered it and the machine now works fine.

I hope this helps

SOURCE: item: kenwood chef km201 Problem:

Hi,

How old is the machine?

The leaking comes from the lower gearbox assembly, ther are two kind of gearbox. There are two kind of vertical drive shaft, 14mm and 12,7mm that goes through the gearbox.

You can try to replace the grease, make sure that is vegetable grease.

SOURCE: kenwood chef A701A mixer not working but blender

could be one of three things
1) the belt is broken to the main gearbox (fairly easy to replace if you can get one)
2) a gear has slipped or broken which means none of the front end will operate.(I have this problem and cannot get the gear body to open)
3) If the top and front worms are turning then the problem is with the planetary gear which again is fairly easy to replace
Bill N