Kenwood chef A901 rough at low speed

Happy_David

Hi all,

These mixers have breaker points like old car engines had. Just like cars, the points wear, sadly the points are obsolete so the best way to fix is to file them.
When they wear you get the mis-fire sound.

Anyway need new parts for your motor look here hxxp://myworld.ebay.co.uk/kenwood-kits2012
lots of cheap parts to get your mixer up and running again.

CHANGE THE HXXP TO HTTP IN THE LINK

Yorkshire_Celt

We have bought a very cheap 2nd hand a901. We have replaced capacitors, triac and resistors. Ordered brushes to replace those too. Sadly, the common problem of erratic operation at low speeds is still there. Just wondering if anyone has actually managed to cure this ? I so I would love to know how you did it. Really hoping we have not wasted our money.

due23

I have just fixed an A901. It ran erratically at slow speeds, with the motor 'pulsing', sounding like it was going on and off all the time. I turned it upside down on the bench and adjusted the two governorr screws until it ran smoothly. Turned it back the right way up and it ran roughly at slow speed again. Left it running for a couple of minutes and one of the capacitors exploded and smoke came out of the machine. I had already bought a set of replacements parts (two capacitors, two resisters and a triac from theinformationcentre_uk on Ebay for £4.99). So I replaced all the parts, following pictures from the Ebay seller. The machine then worked again, but the rough running continued as above. I then read the post from Barneysmom and kefir (thank you both). The motor had a small amount of end play, perhaps 2 to 3 millimetres. Looking at how small the movement of the speed adjuster is in operation, I thought this end play could be the problem. I removed the motor (Remove top cover by undoing 3 screws holding black plastic moulding round fast speed outlet, which allows the whole white plastic top to be removed, exposing main drive belt. Remove belt. Undo 3 cross head screws holding motor in place. Motor comes out of the bottom. Hold it while undoing screws. Note there is a plastic moulding between the top of the motor and the top of the metal casing which needs to go back on reassembly.) On the bottom end of the motor is a metal fan which also has the speed governor weights on it. This is held to the motor shaft with an Allen-head screw. Loosen this and take up any end float (up and down) movement of the motor. I had to remove the speed adjustment mechanism and tap the fan centre carefully but quite hard with a screwdriver and hammer to get it to move. Retightened the holding screw. The motor had no end float but still turned smoothly. I reassembled everything and the speed adjustment was easy to do and the motor ran very smoothly at all speeds. Given the age of these old Kenwoods, the first thing to do it to replace the electronic components, regardless of whether the machine operates or not. My experience shows they are likely to fail any way, and when they do they explode rather than just fail!
Additional info: just applied same process to a second, slightly older, A901. In this case the motor had no end play but still ran a little rough at slow speeds. When removing the governor plate on the previous machine, I noted the projection of the adjusting screws through the plate so I could replace them in more or less the same place to start the adjustments. The projection was about 6 to 7 mm. On this second machine it was 9mm. I adjusted the screws until they projected about 6mm and then adjusted the slow running to give a steady slow speed which increased nicely as the speed dial was increased. The machine now runs very well at all speeds.

lozthejeweller

My wife's beloved A901 started smoking and burning on Thursday evening. I stripped it down today It was all caked up (literally). Both caps had blown so I picked up a couple from Maplin and fitted them. I thought I had fixed it until I read this forum, you see my wife's Kenwood has always had that erratic low idle since her mother gave it to her some years ago so we thought it was normal. Now I have ordered the overhaul kit from the source mentioned in this thread. I'll see what happens after it is fitted!

Little_Vics

I inherited a A701 and sent it off to these guys for restoration, and they were utterly brilliant. Just thought I'd let you know it case you need them in the future:

http://kenwoodchefrestore.co.uk/

powdies

Almost 3 years later, I'm getting back in touch to say no, I never did fix the problem with rough running of my Kenwood Chef! In that time it has been used to death, and it doesn't sound good at low speed, but it works.. It's not nearly as stop start as the videos posted by kefir in Nov 2011, (my misfire noise is much more rapid) and I did try to adjust for any play in the motor shaft - if memory serves, I moved the fan as tight as I possibly could, and it made absolutely no difference.

When I'm feeling brave and have loads of time I may try to take it apart again but it's in almost daily use, and I'm probably not enough of a mechanic. Lots of words I don't understand in the posts above :-(. If anyone feels like explaining to me what is meant by filing the points I'd be very grateful (as I'm practical, though ignorant!). Otherwise, I may just have to live with the roughness forever.. or persuade hubby (who is not at all practical) to buy me a new Titanium!

Wurzy

Yes I've just been working on our Kenwood with the same issue as everybody else, a somewhat rough slow speed. I too have replaced the Triac, Capacitors, Resistors and Brushes and adusted the centrigual speed controller by loosening the Allen grub screw and pushing it towards the armature to take up the play. I am a retired electrical and mechanical engineer and tried, after hours, just about everything. I have come to the conclusion that attempts to get a smooth run were like peeing in the wind, whatever you do you get the problem back.
I would suggest speeding up the the slower speed a little to help alleviate the lumpines. The points filing you mention refers to distributor breaker points which rapidly opened and closed causing back EMF's to be induced in the coil to create vastly increased voltage in the secondary of the coil to fire the spark plugs.
Back to the Kenwood I think best to leave it alone as it will go on forever.

powdies

Many thanks Wurzy, for your reply,and for making me smile, as I was with you until your sentence starting 'the breaker points' and I admit that one could be in Japanese to me :rotfl:

I am reluctant to speed up the lowest speed as it is currently more or less what is recommended, and I use a number of the accessories for my machine. The high-speed slicer is already SCARY fast on lowest speed! I probably wouldn't dare use it if any faster.

But it sounds, from what you say, as if the lumpiness, though unpleasant, is not going to harm anything? If that is the case, I will follow your recommendation to just leave well alone. I love my KC and would be desolate if I broke it by fiddling.

RodM_2

For both repair and upgrade , try :

Kenwood Chef Restore

I upgraded the wife's A901 to great effect.