October 13, 2014 - 10:37pm
Kitchenaid KS55 noise and speed control problem
Hi, I have a Kitchenaid KS55 mixer that's in need of some service, which I'm trying to diagnose and do myself. A few problems have popped up recently, which may or may not be related.
- the speed control has a hard time staying in the off position. it tends to pop into the stir, or even sometimes all the way to the 2 position.
- the above is less of an issue as when in the stir position, it rarely does anything these days. A solid humming sound of the motor trying to work, but no movement. On a similar note, it doesn't even seem to differentiate all the speeds so well all the time. it's kind of just slow, fast, faster.
- In all the speeds up 6 or so, the mixer is making an unpleasant noise. It's not exactly a grinding noise, more like an ominous buzz or hum. I'm either not noticing it as it moves faster, or it's getting less pronounced. In either case, on slower speeds, it just doesn't sound right.
I'm planning on taking it apart to regrease everything, but in the meantime wanted to ask opinions about what these problems might be and what I could be looking for when I have it all opened up. I'm not sure the problem is in the scope of a DIY repair, but I'm pretty handy so figure it is worth a shot.
thanks!
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There are many very good instructional videos on YouTube to help you through the process. It's not very hard to rebuild the gear housing and I ended up replacing all the worn gears, which I got here. They had everything in stock and reasonable prices, and they have downloadable service manuals that are comprehensive. I didn't need any repairs on the electrical end, but it is not very complicated inside the housing and should be quite doable. It took me less than an hour.
From your description of the motor speed problems, they may be linked and it may just need a simple adjustment. To regrease the gear housing you need to get special food-safe grease.
-Brad
thanks! when you replaced your worn gears, what was the sign that they needed to be replaced? I guess I'm trying to figure out if I can determine any parts I need now. Or if I'm just going to have to open it up and see what it looks like in there.
There is probably a composite gear which is intended to strip instead of trashing everything in the transmission. It is only a couple of screws to get the case apart so just do it. There should be plenty of grease hanging around inside the housing that you can redistribute instead of getting new. Mine is 40+ yrs old, used all the time and I have never purchased new grease (also never broken a gear, just redistributed the grease and re-timed the speed control). If you have a broken gear, check for chips in the existing grease. If you find any then you do need to buy a new can of grease and really clean up everything when you put it back together. But still, a full rebuild shouldn't be more than a couple of hours of careful work (plus a week or ten days to get the new parts).
I wasn't sure that I needed new gears, but the grease had broken down and was leaking out of the center shaft. When I saw that the main gears could be bought for under $18, I figured that as long as it was apart, I would just change them. As it happens, they were quite worn, not catastrophically, but they wouldn't have lasted for another 15 years. I also found after going in that the agitator shaft was scored, and since the service manual said it should be replaced if there is any scoring or clouding of the metal, I replaced that, too. Most of the time and effort is in the labor, so I felt a few bucks extra for some parts was a good investment. If you replace the shaft, don't forget to buy the o-ring, because they do go flat after a time. You probably don't need to replace the gasket, but it's usually good practice to do so. Good luck with the project.
-Brad
It has been a few years since I re-greased my very old K45 and it has a mechanical speed control so I doubt the speed sensing is even done the same way on the solid state controllers. What I remember is that there were two adjustments that had to be done in the right sequence to get it set up.
The whole issue could be the speed control itself. I think the solid state version is just a pulse width modulated triac which should come as a single replaceable module (I haven't looked) and a speed sensor that may be a Hall effect device. Either one could fail.
UPDATE: it took me a couple weeks to find the time to carve out some time to do this, but finally got it done the other day. Didn't need grease. there is sooooo much in there, and it all looked in good shape. I tried re-adjusting the speed control plate, and the seemed to help with some. The mixer now stays off! It moves in the stir position, and continues to increase speed as I move the lever. It's still not getting a full range of speed (somewhere around 6 or 8 it seems to top out), but it's better than it was.
I may go in and try to tune the speed control plate again when I have more time. I did that AFTER I had opened up the gear box, so was already a bit tired of futzing and didn't have the patience for trying to get the speeds right.
thanks for the tips everyone!