How to replace the speed control plate - KitchenAid K5SS Mixer Speed Control Plate Kitchen Aid

The starting position for those top speed control plate screws with the lock nuts it 8 full turns in when you fit the plate. Correct adjustment begins in or out from that point. The bottom screw should have been left where it was to start with as that is for adjusting the start position so that when the lever closes the switch contacts to start the mixer the plate only starts moving when the lever moves to the second click. Try and get the bottom one roughly right and then work on the top ones. Turn it to the first click on the speed lever and then EVENLY adjust the 2 top screws to have the planetary turn 13 to 15 times per 15 seconds. Lock up the lock nuts and then check that the bottom screw is in the correct position with speed increasing a small amount as the lever slips into the second click.

Make sure that the carbon brushes are not worn out or if you have already had them out make sure that they have been put back in properly. There is one corner ground off each brush that needs to line up with a blocking corner in the brush holder. Then get your multi meter out and check the unplugged main cable for continuity to the speed control panel. Then check each half of the field assembly for continuity from the speed control plate to a brush holder. Check you have no broken wires to the speed control plate. Check that the switch on the speed control plate is functioning. If all that tests OK I'd replace the phase board, it's worth not much and worth a shot.

There are a few parts that make up the speed control mechanism, the selector can only be the knob and lever. That moves the speed control plate which is the ********* square thing under the back cap that tilts when the lever is operated. There is a governor on the end of the armature under that control plate, that governs the speed by cutting the power through a circuit to maintain an even speed. Above the black control plate is a PCB (phase board I think they call it) that along with the other bits & pieces regulates the power to the control plate.

Remove the back cap over the speed control and look at the speed control plate while operating the speed lever. Make sure the lever is moving the plate in and out. If yes then I would replace the small PCB above the control plate, that is the electronic part of the speed control and not worth very much at all.

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.

Usually when the mixer runs only on high speed it is caused by the control plate adjusted incorrectly or the control plate spring unhooked. Remove the trim & end cover on the mixer and check the control plate spring, if unhooked, attach to bottom of the control plate and squeeze the spring end, also check the speed control plate screws,there are 3 screws on this plate, one at the bottom two at the top, see if adjusting the top screws slows your mixer down.
Next check the wiring of the mixer, Insure everything is wired correctly, to get wiring diagram go to the last page of the service manual. Here is a link to the service manual: http://lib.store.yahoo.net/lib/mendingshed/kitchenaidservicemanual.pdf
If neither of those fixes the problem it is probably a bad phase control board, or a shorted phase control board. With the line cord disconnected, pull the t-bar 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 the phase control is defective and needs to be replaced.
Use the service manual to aid you in taking apart the mixer, trouble shooting the problem and putting the mixer back together, based on the mixer only running at high speed some of the time I would assume it is the speed control phase board.
If you have any questions let me know.
Thank you,
Colleen
Customer Service
MendingShed.com

In the Artisan mixers the problem can be caused by two different parts. First the speed control plate. When you remove the end cover from the mixer the first thing you see is the speed control plate. There are 3 screws on this, two at the top, one on the bottom. Try adjusting the top two screws, to adjust, turn in the control plate adjusting the screws an equal amount.
Also check to see if the control plate spring is unhooked. Remove end cover, and check control plate spring. If unhooked, attach to bottom of the control plate and squeeze the spring end.
It can also be caused by incorrect wiring, check the wiring, the last page of the service manual will be a wiring diagram for your mixer. Here is a link to the service manual. http://lib.store.yahoo.net/lib/mendingshed/kitchenaidservicemanual.pdf
Last, if the control plate is properly adjusted, the control plate spring is hooked correctly and the wiring is correct you will need to replace the speed control phase board. With the line cord disconnected, pull the t-bar 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, the phase control is defective and needs to be replaced.
Thank you,
Colleen
Customer Service
MendingShed.com
800-339-9297

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

It sounds like the speed control plate is not correctly adjusted. If you take the back cover off of the mixer (it is held in place with a screw at the top) and try adjusting the screws on the back plate you may be able to get the mixer to slow down.

You will notice two screws at the top of the speed control plate:
If you turn the top screws one quarter turn, both equally then test the mixer it should adjust the speed. Please make sure not to over tighten or loosen these screws as it can damage the speed control plate! You should not have to mess with any wires attached to the speed control plate or the bottom screw.

If you need more information please see the service manual here: http://ep.yimg.com/ty/cdn/mendingshed/kitchenaidservicemanual.pdf
It will specifically go over how to trouble shoot the mixer and how to adjust the speed control plate.

Please let me know if you have any questions

-Colleen @Mending Shed

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