Won't shift speeds

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.

Take the back cover off, remove the wires. Unclip the spring from the bottom of the plate, don't let it fly back inside the housing. Unlock the 2 screws at the top and undo them. Fit the new plate, each screw 8 turns in to start with. Hook up the spring, put on the wires where they came from. Start machine on speed one, and adjust the top screws evenly to give the planetary 13 to 15 revolutions in 15 seconds. Lock the screws up with the lock nuts. The screw at the bottom is then adjusted so that it gives a slight speed increase when you enter speed 2 from speed 1.

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

Obtain a copy of the Repair Part List for your model from Kitchenaid.com.
Download a Copy of the Kitchenaid Service manual.

http://www.kitchenaidparts.be/centers/servicemanual/mixer.pdf

First, you may want to adjust the mixer's speeds:

1. Loosen the lock nuts enough & Turn the 2 top screws clockwise until they cannot be turned
anymore. Leave the bottom screw alone for now.
2. Use a dab of white paint or paper whiteout to mark the positions of the Phillips screws.
3. Plug in your mixer and Set the speed selector to "Stir".
4. Turn each top screw One full turn couterclockwise (alternating between Left and Right)
Keep making one full turn at the time (for both left and right) until the motor starts running.
5. Put your hand near the Agitator shaft and allow it to brush your finger slightly. Use your
watch or clock and start counting the number of times the shaft touches your finger in
60 seconds. The correct count should be 60 RPM (Rounds Per Minute). If it is less
or more than 60, give each screw 1/4 turn counterclockwise or clockwise and start counting
again. Now tighten both lock nuts.
6. Set the speed selector to "6" and turn the bottom screw either clockwise or counterclockwise
to achieve a speed of 180 RPM.

For your reference, the planetary RPM's for the 5-qt. tilt-head Artisan Stand Mixer are as follows:
Stir speed - 60
Speed 2 - 95
Speed 4 - 135
Speed 6 - 180
Speed 8 - 225
Speed 10 - 280

Second, if the mixer won't run:
Remove the Control Plate Assembly (36), the Phase Control Board (39)
and the motor Governor Assembly (35). Inspect for loose connections,
burnt or damaged components. If they seem to look OK, re-assemble
them and test the mixer. If the motor still won't run, then I might suspect
a defective Phase Control Board (39).

Get a Copy of the Repair Part List from Kitchenaid.com.
You need to adjust the mixer speeds:

Remove the screw holding the End Cover and locate the three screws from the Control Plate.
All three (2 top left and right, and 1 bottom) must be adjusted. Make sure that the Control
Plate is not damaged in any way, contacts are not charred or burnt,etc...

1. Loosen the lock nuts enough & Turn the 2 top screws clockwise until they cannot be turned
anymore. Leave the bottom screw alone for now.
2. Use a dab of white paint or paper whiteout to mark the positions of the Phillips screws.
3. Plug in your mixer and Set the speed selector to "Stir".
4. Turn each top screw One full turn couterclockwise (alternating between Left and Right)
Keep making one full turn at the time (for both left and right) until the motor starts running.
5. Put your hand near the Agitator shaft and allow it to brush your finger slightly. Use your
watch or clock and start counting the number of times the shaft touches your finger in
60 seconds. The correct count should be 60 RPM (Rounds Per Minute). If it is less
or more than 60, give each screw 1/4 turn counterclockwise or clockwise and start counting
again. Now tighten both lock nuts.
6. Set the speed selector to "6" and turn the bottom screw either clockwise or counterclockwise
to achieve a speed of 180 RPM.

For your reference, the planetary RPM's for the 5-qt. tilt-head Artisan Stand Mixer are as follows:
Stir speed - 60
Speed 2 - 95
Speed 4 - 135
Speed 6 - 180
Speed 8 - 225
Speed 10 - 280

Obtain a copy of the Repair Part List for your model from Kitchenaid.com.
Download a Copy of the Kitchenaid Service manual.

http://www.kitchenaidparts.be/centers/servicemanual/mixer.pdf

You need to adjust the mixer speeds:

Remove the screw holding the End Cover and locate the three screws from the Control Plate.
All three (2 top left and right, and 1 bottom) must be adjusted. Make sure that the Control
Plate is not damaged in any way, contacts are not charred or burnt,etc...

1. Loosen the lock nuts enough & Turn the 2 top screws clockwise until they cannot be turned
anymore. Leave the bottom screw alone for now.
2. Use a dab of white paint or paper whiteout to mark the positions of the Phillips screws.
3. Plug in your mixer and Set the speed selector to "Stir".
4. Turn each top screw One full turn couterclockwise (alternating between Left and Right)
Keep making one full turn at the time (for both left and right) until the motor starts running.
5. Put your hand near the Agitator shaft and allow it to brush your finger slightly. Use your
watch or clock and start counting the number of times the shaft touches your finger in
60 seconds. The correct count should be 60 RPM (Rounds Per Minute). If it is less
or more than 60, give each screw 1/4 turn counterclockwise or clockwise and start counting
again. Now tighten both lock nuts.
6. Set the speed selector to "6" and turn the bottom screw either clockwise or counterclockwise
to achieve a speed of 180 RPM.

For your reference, the planetary RPM's for the 5-qt. tilt-head Artisan Stand Mixer are as follows:
Stir speed - 60
Speed 2 - 95
Speed 4 - 135
Speed 6 - 180
Speed 8 - 225
Speed 10 - 280

Get A Copy of the Repair Parts List from Kitchenaid.com
Make sure the Speed Lever and and the Speed Link are in place
and operating smoothly. The two Large black screws you are referring to
are the Motor Brushes Caps. The Carbon Brushes are keyed and
designed to be inserted into the Motor Housing but one way. If you
insert them in wrong, they will not make contact with the Motor Coils
and you mixer will never run.

All you have to do now is adjust the mixer speeds (if necessary):

Remove the screw holding the End Cover and locate the three screws from the Control Plate.
All three (2 top left and right, and 1 bottom) must be adjusted.

1. Loosen the lock nuts enough & Turn the 2 top screws clockwise until they cannot be turned
anymore. Leave the bottom screw alone for now.
2. Use a dab of white paint or paper whiteout to mark the positions of the Phillips screws.
3. Plug in your mixer and Set the speed selector to "Stir".
4. Turn each top screw One full turn couterclockwise (alternating between Left and Right)
Keep making one full turn at the time (for both left and right) until the motor starts running.
5. Put your hand near the Agitator shaft and allow it to brush your finger slightly. Use your
watch or clock and start counting the number of times the shaft touches your finger in
60 seconds. The correct count should be 60 RPM (Rounds Per Minute). If it is less
or more than 60, give each screw 1/4 turn counterclockwise or clockwise and start counting
again. Now tighten both lock nuts.
6. Set the speed selector to "6" and turn the bottom screw either clockwise or counterclockwise
to achieve a speed of 180 RPM.

For your reference, the planetary RPM's for the 5-qt. tilt-head Artisan Stand Mixer are as follows:
Stir speed - 60
Speed 2 - 95
Speed 4 - 135
Speed 6 - 180
Speed 8 - 225
Speed 10 - 280

The K5SS is very similar to the 5-QT Artisan KSM150.
You need to adjust the mixer speeds. Obtain a copy of the K5SS Repair Part List from Kitchenaid.com. Remove the screw holding the End Cover and locate the three screws from the Control Plate. All three (2 top left and right, and 1 bottom) must all be adjusted. 1. Loosen the lock nuts enough & Turn the 2 top screws clockwise until they cannot be turned
anymore. Leave the bottom screw alone for now.
2. Use a dab of white paint or paper whiteout to mark the positions of the Phillips screws.
3. Plug in your mixer and Set the speed selector to "Stir".
4. Turn each top screw One full turn couterclockwise (alternating between Left and Right)
Keep making one full turn at the time (for both left and right) until the motor starts running.
5. Put your hand near the Agitator shaft and allow it to brush your finger slightly. Use your
watch or clock and start counting the number of times the shaft touches your finger in
60 seconds. The correct count should be 60 RPM (Rounds Per Minute). If it is less
or more than 60, give each screw 1/4 turn counterclockwise or clockwise and start counting
again. Now tighten both lock nuts.
6. Set the speed selector to "6" and turn the bottom screw either clockwise or counterclockwise
to achieve a speed of 180 RPM.

For your reference, the planetary RPM's for the 5-qt. tilt-head Artisan Stand Mixer are as follows:
Stir speed - 60
Speed 2 - 95
Speed 4 - 135
Speed 6 - 180
Speed 8 - 225
Speed 10 - 280

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

CE is the marking that shows its european conformant.  I think the difference is mostly in terms of the no volt interlock switch.  This means the KA style N50 bowl won't work with the CE models - too low.