20 Most Recent KitchenAid KSM90 Ultra Power Series Stand Mixer Questions & Answers

I called KitchenAid about this issue with my mixer. The agent on the phone told me they are aware that it tends to happen to some mixers after they sit for some time. Basically, a "lifetime" of grease has been packed into the assembly and it is normal for it to release grease on occasion. I was told to run the mixer at 10 for at least 2 minutes to get it going and I should see a reduction in the oil leak. I had about a tablespoon worth of oil dripping down off the assembly. I was told that if over time it seemed to amount to about 1/4 cup then I should call to see about repairs due to a potentially bad seal. I was also told that the repair for that would most likely NOT cost the same as a new appliance.

KitchenAid KSM90... | Answered on Nov 10, 2018

The Service Manual for your mixer can be found at:


Among the causes for the mixer not turning on are (in no particular order) --

The leaf-spring switch on the Control Plate is not making contact.
The Phase Board is defective.
Brushes need replacement.
Brush chamfered side not correctly oriented.
Bad armature or field coil.
Seized motor bearing.
Detached or broken Control Board spring.
Speed Control Link plastic end broken.

KitchenAid KSM90... | Answered on Jan 18, 2018

You will find that the fuse gear has failed, it's either been overloaded or it's just worn out from use or maybe the lubricating grease has gone old and needs changing. That will be change the failed gear and replace the grease.

KitchenAid KSM90... | Answered on Jan 02, 2018

Kitchen Aid is 100% correct. The cause of the problem is age and lack of regular use, the oils in the gearbox grease separate from the solids over time and the oil then leaks out at the planetary and sometimes where the 2 case halves join under the silver trim band.
If you are up for a small job knock the chrome trim ring around the planetary off and clean it out and wipe around the area it covers. It is called a drip ring for good reason, you may find it full of oil.
The grease Kitchen Aid used in their mixers is Food Grade and it's harmless.

KitchenAid KSM90... | Answered on Nov 02, 2017

More likely the pedestal base is bent. Your local service agent has probably seen it before and should be able to bend it back flat again. It's a brutal process with a heavy soft hammer that you probably won't want to see.

KitchenAid KSM90... | Answered on Jul 25, 2017

There are several things that regulate the speed, we will assume that the adjustment has not been messed about with. If the governor on the motor armature that presses against the underside of the square black speed control plate at the back has not flown apart then I would replace the small pcb (phase board) on the top under the back cover. One screw and 4 wires hold it on.

KitchenAid KSM90... | Answered on Jun 23, 2017

The head bounce sounds as if the locking hook is not engaged properly when you slide the head-lock lever to the locked position.

If this is the case, you will need to disassemble the mixer to make sure the link from the lever to hook is not bent. Another possibility is that the slot in the base the hook engages. If this is broken away, the hook will not be able to hold the head in place (I sure hope that this is not the problem).

The Service Manual can be found at:


KitchenAid KSM90... | Answered on Apr 28, 2017

Just recheck that you really have put the brushes back in the right way, use a torch and look in the hole. The brushes can each go in 4 ways, only one of which will work. Look for the blocker and line it up with the cut off corner on the brush. It's normally at the back, one side at the top the other at the bottom. After that you need to be looking at everything you have done for a booboo. I doubt it will be water ingress. Make sure the switch contacts come together when the lever moves to position 1.

KitchenAid KSM90... | Answered on Mar 18, 2017


KitchenAid KSM90... | Answered on Nov 05, 2015

Solution for these KitchenAid Stand Mixer Models
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Fix KitchenAid Stand Mixer Workshop Service Repair Manual Download

KitchenAid KSM90... | Answered on May 15, 2015

Hello Heather,

Either the grooves on the bowl lock plate are worn out, or the grooves on the actual bowl are worn out. I would start with replacing the bowl lock plate. Here is a link to the part: KitchenAid Mixer Bowl Lock Plate 4163032

This part is really easy to replace, it is held into place with three screws, remove those screws (make sure to hang onto those you will need them to re-install the new part). then you should be able to pop the old plate out. To install the new plate like up the screw holes, and press into place, sometimes you need to lightly tap it into place with a rubber mallet as it is suppose to be a very tight fit.

Once that has been replaced your bowl should lock into place tightly. However there is always a chance that the bowl has been worn down and may need to be replaced. Here is a link to the 4.5 Quart bowl: KitchenAid 4 5 Quart Stainless Steel Bowl

- Colleen @ Mending Shed.com

KitchenAid KSM90... | Answered on May 05, 2015

If the mixer is working on the other speeds, it needs adjustment to the speed control plate. See the Service Manual:


KitchenAid KSM90... | Answered on Mar 16, 2015

You really need to get a Multi meter and follow the power, you have replaced the phase board so we can probably discount it being that.
First check that the switch contacts behind the black control board are really touching when you move the speed control lever to turn the mixer on.
Next the cable, do you have continuity from the wall plug to the control board on phase & neutral, (Check green earth wire as well for the sake of safety) that will be the black wire and the white wire on the 2 lower plug in contacts on the black control board at the back.
Next remove the carbon brushes, do they have reasonable length and most importantly are they fitted correctly with the corner key aligned with the blocker at the bottom of the brush holder.
Next with brushes out check for field winding continuity. On the other side of that black control board to where the power comes in there will be a red wire and a white wire that disappear into the motor housing. One of the wires will have a circuit to one of the brass brush holders and the other wire will have a circuit to the other brush holder. The resistance of both of those circuits should be pretty much identical.
After you have done those tests you should begin to have a clue as to where the problem lies.

KitchenAid KSM90... | Answered on Feb 18, 2015

I had a similar problem where the mixer would also go to fast speed right away. On the back at the top was a screw that was loose. After tightening this screw I had 4 speeds but no stir speed. I unscrewed that screw and a bolt fell out. This bolt went to threads on the inside of the area covered by that back plate. I put that bolt back on and tightened it and the corresponding one on the other side and wala the mixer works perfectly at all speeds. Hope it helps. Make sure mixer is unplugged before attempting anything like this (wires are exposed when the back plate is removed - some kind of flexible circuit board).

KitchenAid KSM90... | Answered on Feb 07, 2015

Something must be broken if the motor is turning and the planetary is not. It will be one of the following, we will start from the first point of contact with the armature
1) Worm gear broken (fuse gear) you say no teeth broken
2) Worm gear not broken but whole unbroken plastic part not gripping aluminium boss
3) Pin through worm gear broken or missing
4) Pin through centre (or bevel) gear broken or missing
5) Pin through small gear in planetary broken or missing
6) Pin through planetary hub centre shaft broken or missing

The most common ones in order of likelihood are, 1, 2, 3 and 6

KitchenAid KSM90... | Answered on Dec 29, 2014

Hi NORMR123, it sounds like your Switch Lever has loosened up and you just need to get to the attaching screw to tighten everything up. (I trust you reinstalled the motor brushes correctly so your mixer will run. Many folks attempt repairs by removing the brushes thinking it will provide access to the inside, then reinstall them incorrectly and wonder why their mixer doesn’t work.)
Be sure you have the Parts List manual on hand. If you're lacking one, you can download a PDF version from the KA website at: http://www.kitchenaid.com/flash.cmd?/#/page/home.
Click on Customer Care>Locate Manuals & Guides> then enter the visitor type “Consumer” and the 6 character model number, in your case use KSM90P, in the Model Number box. Select one the files listed for your model that appears under Parts List (16): KSM90PSWH0.pdf (354.08 KB) and save that file to your PC (check to see if this matches your mixer model).
Although not providing step by step instructions, the Parts List manual provides an exploded view of the various component assemblies allowing you to see how the mixer all fits together. It is helpful for the disassembly, troubleshooting, and reassembly of your mixer.
Turn to pages 6 & 7, titled “Motor And Control Parts”, and locate Ill. Nos. 1, 2, 3, & 4. #1 is your Pivot Screw, which may have loosened over time. #3 is your Switch Lever and stud. Check the detent is present or rubbed down. If that’s the case, you may want to replace it.
As far as parts go, here are five potential vendors in no particular order: RepairClinic.com; mendingshed.com; searspartsdirect.com; partstore.com; and Grainger.com (for grease). Prices can vary widely between vendors, so do some comparison shopping.
Finally, here are some links to several excellent websites that detail the disassembling/reassembly of a KA Mixer.
Between these three websites and their excellent pictures and descriptions and your Parts List manual, you should now be able to completely disassemble, inspect/adjust/replace your Switch Lever, and reassemble your mixer. Good luck, I hope this helps. Howard, Burke, VA
If this solution was helpful, please rate it, thanks! – hslincoln

KitchenAid KSM90... | Answered on Dec 09, 2014

Well first thing; here is the link to the KitchenAid site where your parts list can be found.

Next, the parts list will tell you what the part number is for the brushes and all the parts that make up the brush assembly. If you need to replace any part other than the brushes you will need to do a full tear down to do that. Also; remember that there are four different ways to replace the brushes but only one way will work. You need to be very careful to remember which way the old brushes come out, there is a beveled edge on one side of the brushes and the new brushes need to go back the exact same way or they will not reach the commutator on the armature and the mixer will not work until the brushes make that contact with the armature.
Lastly the reason that your mixer gets out of time is that over time, 8-10 years of use, the nuts on the speed control switch that hold the three timing screws in place simply get loose due to vibration and the screws can rotate in or out. Some times the screws vibrate loose and the mixer just will not turn on next time the mixer is used. Peeps then think it's broke and will not work so they sell it for parts and by a new mixer. When the only thing they need to fix it is a Phillips screwdriver , a small 3/8th open box wrench and about 20 minutes time to fix it.
Anyway I hope that this helped to answer your question. Please let us know if it helped and if not let me know and I'll try to help fixya.

KitchenAid KSM90... | Answered on Sep 03, 2014

If it looks like the photo beside the blue panel above I'd say it's a KSM 90 so you should be able to find your motor brushes and a downloadable manual with the help of Google. If you are in NZ I have brushes and can copy the manual for you.

KitchenAid KSM90... | Answered on Aug 31, 2014

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