Kenwood Chef Repair
circa 1961 wow!
I was asked to look at a Kenwood Chef A901 from the 70's must say they are really well built. Lot of stuff on the web ranging from misinformed forums to dedicated repairs site. All with one thing in common - not enough information. I will add some photos for disassembly, if anyone is interested.
Smoking, smell of burning, no control of the speed or motor dead.
1) Motor speed controller.
Press the green reset just in case it has operated. The controller had failed due to the X capacitor going short circuit. the 56Ω and 220Ω (ohm) resistors on the triac should also be replaced (I found the 220Ω triac gate resistor was OK but the 56Ω input resistor was open circuit).
0.15uF (150nF) 275v X capacitor*
0.047uF (47nF) 275 X capacitor*
(*make sure these are true X class "across the mains" capacitors)
56Ω resistor (looked like a 1 watt increase to 2 watt)
220Ω resistor (looked like a 1/4 watt increase to 1 or 2 watt)
2) To be sure - replace Motor Brushes
5.5mm x 7mm x 18mm long (spring 6mm OD 18 turns plus 2 closed turns either end. 35mm long 0.5mm wire diameter). I am looking for a supply of these now (about £4 off Ebay).
You will have to remove the motor by taking out the three mounting screws in the top housing. (take note of the direction of white nylon spacer between the housing and motor, if it falls out (concave part of molding facing towards top of machine)
3) Mains cable
Replace the 20-30 year old cable (!) and change the fuse to 3A (people often put 13A fuses in when the motor stops)
4) Gear Box
The gear box has a habit of dripping liquified grease so replace that while it is disassembled. Will add details when I get it finished
5) Drive Belt
The belt can snap but make sure there is no problem with the gearbox before replacing
Everything available from Ebay. Lot of second hand bits. Components from Maplin or RS (go to the trade counter) Grease is available (Rocol Foodlube or similar)
6) Make sure you check the rubber feet - if they have shrunk with age, reducing the space for air to circulate under the machine, make some new ones to regain the height to avoid overheating