The mixing head, the part that flips up is loose. when i am mixing and i try to lock the head i have to lip it slightly to be able to lock it. after that it makes a noise as the beater, either the paddle or the wisk goes around. i did not drop anything into it, so this is just a new, non-provoked situation.

Don't forget if it is new it is under manufacturer warranty.

Make the beater isn't too low and fouling, because the bowl is set too high? Try to lock with no beater.

Slide the locking lever toward the rear and lift up the head.

The head unit is not locked in place. If the lever is in the lock position and it still bounces, the cam lever inside has either snapped off or became loose.

You can try moving the lever slightly up or down while moving it forward to see if this will free it it or make a difference. Otherwise, the spring inside may have snapped or the speedlink cam may have came loose or broke. Either one will require the top end assembly to be removed to replace these parts.

If you're still having this problem, here's what I did a few minutes ago that fixed it. Lift the head, then turn the screw that connects the head to the base to the left. You're basically unscrewing it. That screw regulates how high or low the beater is. Unscrew it a little at a time, and lower the head and try to lock after each turn. The head will gradually get in a more locked position. Keep turning the screw till the head finally locks in all the way. Read the "beater to bowl clearance" section in the manual.

flip head up; and, there is a adjust screw underneath. turn screw out ccw to raise head.

Hi, KLOEHR, your beater will not lengthen by losing a screw. However, if you lost your Beater to Bowl Clearance adjustment screw, then it might appear that your beater had ‘grown’ because now the beater may be touching the bottom of your mixing bowl, where previously it had not. Simply said, the beater didn’t grow the mixer head drooped.
You don’t say if you have a ‘tilt-head’ or a ‘bowl-lift' mixer, but you can easily download a PDF version of your Owners Manual from the KA website at: (http://www.kitchenaid.com/flash.cmd?/#/page/home).
Click on Customer Care>Locate Manuals& Guides> and enter the 6 character model number (in your case, use KSM5PS)and select the last file listed that appear under Owners Manuals: KSM5PSWW0.pdf (2930.74 KB) and save that file to your PC. You’ll need to have Adobe Reader to be able to open it. Turn to Page 11 and you will find the instructions for adjusting the mixer head height. I have extracted the instructions below:
Beater to Bowl Clearance
Your mixer is adjusted at the factory so that the flat beater just clears the bottom of the bowl. If for any reason, the flat beater hits the bottom of the bowl or is too far away from the bowl, clearance.
Tilt-Head models
• Unplug mixer.
• Lift motor head.

• Turn screw (A) SLIGHTLY counter clockwise (left) to raise flat beater or clockwise (right) to lower flat beater.
• Make adjustment with flat beater, so it just clears surface of bowl.
If you over adjust the screw, the bowl lock lever may not lock into place.

Bowl-Lift models
• Unplug mixer.
• Place bowl lift handle in down position.

• Turn screw (B) SLIGHTLY counter clockwise (left) to raise flat beater and clockwise (right) to lower flat beater.
•Make adjustments with flat beater, so it just clears surface of bowl.
If you find the adjustment screw missing, you’ll need to replace it. But now you’ll need
I hope this helps! –Howard, Burke, VA
If this solution has helped you, please rate it, thanks! - hslincoln

JOE:You don’t say if you have a ‘tilt-head’or a ‘bowl-lift' mixer, but you can easily download a PDF version of your Owners Manual 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 (in your case, use KSM90P)and select the last file listed that appear under Owners Manuals:KSM90PSWW0.pdf (2930.74 KB)and save that file to your PC.You’ll need to have Adobe Reader to be able to open it. Turn to Page 11 and you will find the instructions for adjusting the mixer head height.I have extracted the instructions below:
Beater to Bowl Clearance
Your mixer is adjusted at the factory so that the flat beaterjust clears the bottom of the bowl. If for any reason, the flat beater hits thebottom of the bowl or is too far away from the bowl, clearance

Tilt-Head models
• Unplug mixer.
• Lift motor head.

• Turn screw (A) SLIGHTLY counter clockwise (left) to raise flat beater or clockwise (right) to lower flat beater.
• Make adjustment with flat beater, so it just clears surface of bowl.
If you over adjust the screw, the bowl lock lever may not lock into place.


Bowl-Lift models
• Unplug mixer.
• Place bowl lift handle in down position.

• Turn screw (B) SLIGHTLY counter clockwise (left) to raise flat beater and clockwise (right) to lower flat beater.
•Make adjustments with flat beater, so it just clears surface of bowl.

I hope this helps! –Howard, Burke, VA
If this solution has helped you, please rate it, thanks!.hslincoln

This sounds like an issue of beater to bowl adjustment, which can come out of alignment naturally over time and with use of the machine.

If the flat beater is striking the bottom of your bowl, this may cause the locking mechanism to loosen and may cause the mixing head to "bounce" during use.

Your Use and Care Guide will cover the "beater to bowl adjustment," which you can do at home in a few minutes with a flathead screwdriver.

This may have a simple solution: This sounds like an issue of beater to bowl adjustment, which can come out of alignment naturally over time and with use of the machine.

If the flat beater is striking the bottom of your bowl, this may cause the locking mechanism to loosen and may cause the mixing head to "bounce" during use.

Your Use and Care Guide will cover the "beater to bowl adjustment," which you can do at home in a few minutes with a flathead screwdriver.