Aristan Open/Close I don't mean speed control switch. I mean the switch to open or close the mixer. I am from poland and kitchen aid support wont help me. My mother in low has similar Mixer and in her model when she open the switch it goes back to close position (like a spring). And in my model it doesn't. Is it possible that I send you some photos of it.

Question edited for clarity.

The drive train probably need cleaning and re-greasing, but there is also a gear that wears out.

https://www.google.com/search?q=Kitchen+Aid+Mixer.+How+to+fix+a+grinding+sound+when+switch+is+on+Medium+speed

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Look under the back cover for something amiss with the black speed control plate. The switch is mechanical not electronic so something is keeping the contacts closed.

Could also be a broken wire to the control plate. It's not very often the plate itself. Just looking in there while operating the lever may reveal something. The shaft at the bottom that moves the plate closes a set of points to start the mixer, maybe the points are loose and not closing when they should. Just be careful operating it with the cover off and alive.

If your mixer only runs on high speed there are 3 things that can cause that. The first thing to check will be the speed control plate, Remove the trim and end cover on the mixer, the first thing you should see is the speed control plate, this has 3 screws on it, try adjusting the top two screws 1/4 turn, this should slow the mixer down, do not over tighten. Also check to see if the control plate spring is unhooked. If the spring is unhooked, attach to bottom of the control plate, and squeeze the spring end.
If this does not fix your mixer, check the wiring of the mixer, you can locate a wiring diagram on the last page of the service manual.
If the speed control plate is adjusted correctly and all the wiring is correct it will be your speed control phase board. You can test the speed control phase board to see if it is shorted. With the line cord disconnected, pull the t-b ar contacts to open, and insert a piece of paper between them so they cannot close. Reapply power-the mixer should just run or buzz trying to run. If it operates at full speed, teh phase control board is defective and needs to be replaced.
Here is a link to the service manual: http://lib.store.yahoo.net/lib/mendingshed/kitchenaidservicemanual.pdf
This will aid you in taking the mixer apart, troubleshooting and putting it back together, remember the wiring diagram is the very last page.
Thank you,
Colleen
Customer Service
MendingShed.com
800-339-9297

Call the Kitchen Aid small appliance warranty office and they will tell you where the authorized repair person is that is close to you.

Unfortunately you will probably need to split the gearcase to sort out the speed control arm.

The switch on the titanium has a flimsy week point and is always breaking. This is a stupid economy by Kenwood when there is now so much good competition. Mine broke after only 6 months and Kenwood were less than helpful suggesting I took back to where I bought it - 500 miles away!! I wish I had bought a Kitchen Aid

Hello oldandnew2,

The problem is in the speed switch, the contacts are closed and not allowign power to go thru it is a common problem with all of the kitchen aid mixer over a period of time the contactors get carbon build up. Take the back off and look at the bottom inside and there should be two little contactors see if the are burnt and try and clean them. If this does not work you will need a new one, post back the the tread and I will locate you one.

Thank you for being a member of FIxYa.

Here is how your speed control works:

Speed Control
The speed control of the mixer is attained through the use of a governor assembly mounted at the rear of the control plate assembly.
The electrical circuit is made and broken by the action of the fly ball governor revolving against the control plate.
When the switch lever is moved to an ON position, the position of the control plate with respect to the governor is changed by the action of the switch lever.
Thus, when the control plate is set close to the governor, a relatively low speed of the motor causes the governor to make or break the mixer’s electrical circuit through the control plate.
When the control plate is set farther away, a greater motor speed is required before the governor starts breaking the circuit.
The action of the governor is such that the speed of the motor will remain constant for a given setting of the control plate within certain loads.
After certain loads have been exceeded, the speed of the motor will drop to meet the torque requirements of the given load.
Speed is controlled by the governor and the control plate in conjunction with the phase control.

TRIAC RMS VOLTAGE
BOTH CONTACTS OPEN - 40 VOLTS
ONE CONTACT OPEN - 80 VOLTS
BOTH CONTACTS CLOSED - FULL VOLTAGE
NOTE: The triac regulates the power the motor sees depending on control board contacts.
A device called a triac is a part of the phase control circuit.
This device determines the amount of power the motor sees dependent upon the condition of the control board contacts.
If both contacts are open, about 40 volts RMS is applied to the motor and about 80 volts is applied when either contact is closed and the other is open.
When both contacts are closed, the triac is full on; consequently, full power is applied to the motor. In this way, the speed is controlled.
If the mixer motor begins to run too fast for a
particular speed setting, one or both contacts open, which cuts back on the voltage the motor sees, thus slowing it up.
If the motor operation becomes too slow, one or both contacts will close, applying the needed voltage to the motor to sufficiently increase motor speed.
This is always accomplished through the triac.
The control plate contacts control the triac, and in turn, controls the amount of power supplied to the motor.

The control Plate for your mixer is PN
W10119326
http://www.marbeck.com/mixers_kitchenaid_parts.html

If your not good with tools / meters or tedious repairs do NOT attempt this yourself.
The service manual for your mixer can be found here
http://www.f-ems.com/download/DownLoad.aspx?DocsID=082009012917

and is:
LIT4177310-C

Hi again, LESZCZ2. I believe you are speaking about your Speed Control Lever Assembly “switch”. Is that correct? From the symptoms you describe, it’s very possible, as you feel, the Control plate spring is broken or has become unhooked from the lever. You should be able to inspect this yourself and determine if that’s happened with just a little effort.
Be sure to have your Parts List Manual on hand, too. If you don’t have the original you can easily download a PDF version from the KA website: (http://www.kitchenaid.com/flash.cmd?/#/page/home).
Click on Customer Care>Locate Manuals& Guides> and enter the 6 character model number, KSM150 and select one the files listed for your model that appears under Parts List (61): KSM150PSWH0.pdf (773.44 KB) and save that file to your PC.
Turn to pages 8 & 9, titled ‘Motor And Control Part’. Locate Illus. Nos. 1, 2, 3 & 4, Pivot screw, Spring washer, Speed control assembly lever, and Control plate spring, respectively. Carefully inspect these parts to see if they have not come loose, particularly the pivot screw and spring washer. Also check to see if the spring hasn’t become unhooked from the lever or broken.
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. Prices can vary widely between vendors, so do your comparison shopping.
If you feel troubleshooting and repairing is beyond your capability, then I would seek out a local small appliance repair shop in your area. KA Customer Care can give you names of local KA authorized repair shops in your area, but you can also do an online search to supplement what KA may provide you. Call to explain your circumstances and find out their hourly rate and get an estimate of what they think it would cost to repair your mixer. Also, always obtain three or more estimates – do some comparison shopping.
Good luck and have fun. I hope this helps. Howard, Burke, VA
If this solution was helpful, please rate it, thanks! - hslincoln