This is my vacuum cleaner.
It’s a Miele S5210. It’s a very, very good vacuum cleaner. Well, it was until the point that it broke! Actually I was somewhat responsible for that. For a little while now I have been restoring a car (OK, almost 6 years but I am nearly done – www.asciimaton.co.nz/pics). After weeks of filling and sanding of filler I finally sent it off to the panel beaters to be painted. This left me with a garage full of sanding dust. I swept up what I could the used the vacuum to clean up the rest. Unfortunately your average house vacuum isn’t really designed to handle lots of very, very fine filler dust. I ended up clogging it up and the motor stopped running smoothly and instead started stuttering. I needed to take the vacuum cleaner apart to clean it and remove all the dust so it would run properly again. What follows is the procedure I used to take the vacuum cleaner apart. I imagine the process is probably similar to other Miele vacuum cleaner models.
I was inspired to do this page after I found the following page online for a different Miele model (a Miele s300): http://www.sannerud.com/house/miele.html
You don’t need many tools to take the vacuum cleaner apart. Just a Torx T20 driver and a small flat screwdriver to push on the plastic clips that holds the parts together. All the screws used to hold it together are the same. The Torx bit shown here is actually a tamper proof Torx bit with a hole in the middle but it works fine on the screws. Click on any of the pictures for a larger view.
First unplug the vacuum cleaner and remove the bag and all the filters. The small silver honeycomb filter just clips in place. Remove this so you can then remove the lid.
The lid just slides onto the hinges and two small square clips hold it in place as shown above. Depress the small squares and then slide the lid off the hinges.
The large honeycomb filter is also just clipped in place. Carefully push back the two clips shown circled above and the filter should come out.
The plastic piece at the rear between the two buttons is also just held in place by clips. Brute force will remove this. Just yank it upwards and it will pop loose.
With the rear cover removed you should see two screws holding the speed selector part in place. Remove these.
With the two screws removed the speed selector can be removed by pushing in the small clips that hold the front of it in place and lifting it off. This piece just contains the knob that controls the speed. The knob has a stalk that sticks down underneath it that fits into a selector switch on the electronics board.
The top cover is held in place with four screws shown, two at the front and two down deep holes in front of each button. Undo these then the top cover should lift off.
With the top cover removed you can see the electronics board. It’s pretty simple really and doesn’t have much on it. The board should be free to pull off now. The only thing holding it in place is the connector shown above. Simply unplug this connector and the board will lift off.
With the electronics board removed you should be able to see the screws holding the inner cover in place. There are three at the back and one in the centre as shown above. Remove all these screws.
As well as the four screws there is a clip either side of the cover on the sides of the vacuum. You can simply pop these apart by hand then the inner cover should lift off. There is a small rubber hose that goes between the cover and the cord retractor mechanism which you also need to disconnect from the cover (it will probably just fall off anyway).
With the inner cover removed you can now remove the motor (which has a foam pad over it) and the cord retracting mechanism. The only trick here is to unplug the connector that joins the two together.
The motor and cord retractor will simply lift out. I gave everything a good cleaning to get all the dust out. I used my air compressor to blow it all clean. With all the dust removed from the motor I sprayed it’s brushes with electrical contact cleaner. I didn’t go as far as dismantling the motor itself (March 2010 – OK, I did eventually See below!).
The brushes are either side of the motor and I simply sprayed cleaner into the hole at back of them.
After letting the contact cleaner dry I put the motor, cord retractor and electronics boards temporarily back in place the tested the vacuum. You need to be VERY careful doing this as nothing is properly attached and there are exposed mains connections that will bit you it you touch them (don’t ask how I know). Also the vacuum motor is extremely loud when not encased in plastic!
Once everything was cleaned and working again reassembling the vacuum cleaner is basically the revers of taking it apart. Make sure you reattach the small rubber hose and also make sure the cord and plug are free and don’t get caught when screwing all the pieces of the case back together.
After my cleaning and spraying the motor with contact cleaner the vacuum is working nicely again. I know now I should really get a nice shop vac for cleaning the garage and leave the Miele for purely domestic duties!
I can really recommend these vacuums. They are good value for money and very powerful. And now, having seen how they look inside, I can say they are very nice quality too.
Update March 2010.
I have had a few people comment that this page was useful so I decided to post the second part of my vacuum cleaning story in case people find this further detail helpful.
My cleaned up vacuum worked well for a little while but then the motor started stuttering again until eventually it stopped running altogether. Another tear down was in order. This time right down to the motor itself. Again the nice design of the Miele made this an easy job to tackle.
First you need to remove the motor from the vacuum as described above. Then carefully tap off the metal shield on the end of the motor exposing the blower fan. Next remove the nut holding the blower fan in place. Now it was a few months ago that I did this but from memory the nut is a reverse threaded one, i.e. turn it clockwise to undo it. This allows you to pull off the aluminium blower and the flat spacer washer.
Next you can lift out the two carbon motor brushes. These are simply held in with spade connectors so you can just pull them straight out. In the picture below you can see the female spade socket on the face of the stator housing.
The brushes are nice and long so should last a very long time.You can see the long male spade connector on the bottom of the brass housing. You can also see how despite my previous cleaning this brush is still covered in sanding dust. If I didn’t mention it above I should say don’t sand filler off a car (http://asciimation.co.nz/pics/page18.html) then use this vacuum to collect the dust!
With the brushes removed (and cleaned up with electrical cleaner) you can remove the stator. There is a metal spring clip that holds it in place. If you press this down the stator should then slide out.
The electronic controller is attached to the stator and will come put with it. You can see the top of a TO220 type device sticking out of the top of the plastic housing. We get to that in a minute. The inside of the stator and housing were both covered in the sanding dust so I cleaned these up as well.
Next you can carefully pull out the rotor. This has bearings on each end and the lower bearing is a press fit into the housing. You need to carefully pull this out. The rotor will come out in one piece. Be careful not to lose the little flat spring washer though.
The observant of you will probably have noticed one of the problems with the motor. The commutator on the end of the rotor, that ring of copper strips the brushes rub against, are filthy and scored. To fix this I carefully mounted the rotor in my mini-lathe. You only need to grip it very lightly in the three jaw chuck. I made sure it was running true and turned it on. I then used some fine wet and dry sandpaper folded into a long strip to carefully sand down the commutator.
I didn’t try to get the commutator perfectly smooth as I didn’t want to sand too much away. It still has a few small scores around it but it doesn’t need to be perfect. The deep scoring is actually where the edges of the brushes are in contact with the commutator so the brush is in contact with smooth copper on most of it’s face.
Next I cleaned up the aluminium blower which was quite clogged with dust. A bit of electrical cleaner and a poke around the fins with a long cable tie did the trick.
After doing all this and cleaning everything to remove all the dust I reassembled the motor. Since I had given it a good clean with electrical cleaner I left the motor on top of my dark coloured garage roof to make sure it was fully dry before trying to run it again. I wanted to make sure all the cleaner had evaporated out of the motor and windings.
Unfortunately after putting it back in the vacuum cleaner and reassembling everything (with a little Loctite around the rotor bearing where it pressed into the housing) the motor was still dead! I had to take it apart again. This time I removed the motor, opened that up and removed the motor electronics. Again thanks to nice design this module just unclips since it is held in place with spade connectors.
The electronics on the motor are incredible simple. Basically it’s just a TRIAC and what I think is a thermal cutout device.
About now the problem was pretty obvious. This TRIAC was burned out! A close inspection and a little prodding showed that TRIAC was burned out. Two of the legs were not even connected to the body anymore.
I am not sure why this happened. I am guessing a combination of a badly connecting and arcing commutator and a motor clogged with sanding dust ended up cooking things. The TRIAC itself is a T2550h 600T which is a 25 amp TRIAC. These are available in NZ but not from the easy places like Jaycar or Dick Head Smith (who don’t really do electronics anymore despite their name). You can probably get them from the bigger suppliers like Farnell or RS but they would cost a bomb and you might not be able to buy just one. So I looked on eBay and found someone in the UK sells them for just a couple of quid. I ordered one of them.
This is the data sheet for this particular part: http://www.datasheetcatalog.org/datasheet/stmicroelectronics/6697.pdf
Once that arrived a week or so later it was a simple matter to unsolder the dead part and solder in the new TRIAC. I reassbmbled everything again (after this many time apart you get good at this bit) and finally everything was working again!
All that was actually done several months ago and the vacuum cleaner is still working happily now. I know these things aren’t supposed to be customer serviceable but it is nice to see that they are engineered in a way that means a customer with the right skills can successfully get in there and fix things.
Update September 2015.
OK, another update. My vacuum cleaner died again! But once again I was able to resurrect it after having to refer to my own instructions here to remember how to take it apart.
The issue was that it just stopped. Was running then just died and wouldn’t work again. I opened it up and found this:
That is the Klixon thermal cutout thingy. Interesting, right back in 2011 a visitor called Dave left this comment for me:
Thanks for a first-class tutorial on the Miele S5210. Well done, it saved me a load of time and effort.
My vacuum cleaner suffered the same fault as yours, and I have found out what caused it in my case. Taking apart the motor, I removed the triac PCB assembly. I noticed that one leg of the fuse had fractured, and there was evidence of sparking across the fracture. Prior to the failure, the vacuum motor had suddenly started making more noise, which turns out to have been due to the intermittent connection through the thermal fuse. After a few minutes, the sparking destroyed the triac and the unit died…but the thermal fuse was still OK! (apart from having one leg sheared off). I was able to repair the sheared leg and replaced the triac, and all is now fine and tickety-boo.
So the problem in this case was not poor filtering, but cracking of the thermal fuse, probably caused by the vibration. I wonder if the motor manufacturer ever assessed the thermal fuse for vibration susceptibility….
By the way, the “thingy” is a Klixon thermal fuse, rated at 18A. It’s hard to find any equivalent fuses, because you need the high current rating, and nobody seems to make an 18A rated fuse quite as small as this one.
Here’s a link: http://www.klixon.com/klixon/motor-protector-3mp-self.htm
Those comments are number 25 and 26 in the comments below btw. The exact same thing had obviously happened to mine. I said then I didn’t know how I would fix it, now I do!
The fuse is two metal sides joined together with an insulator between. The legs are just extensions of the cans. The fuse itself seems fine so I just needed to repair the leg. I used a piece of desoldering braid as a new leg. I used a piece saturated in solder and soldered it to the board first then to the side of the fuse.
Make sure the new leg is only connected to one side of the can. The tricky thing about this fuse (or any fuse) is normally it is a conductor and it needs to go open circuit in overload conditions. If you are not careful the new leg could actually be short circuiting the fuse rendering it useless. You vacuum will work but there will be no protection there. Of course the fuse is normally conducting so just measuring it with a multimeter won’t tell you anything. You have to inspect it visually to ensure it’s not shorting.
After putting it all back together the vacuum works fine again. While apart I gave it a good clean and checked the commutator and brushes. The commutator showed no more scoring since last time and a quick rub over with some glass paper left it clean. The brushes still have a lot of life in them.
Interestingly they wear unevenly. You can compare the wear to the last photo taken over 5 years ago now above. These days I have a dedicated shop vac so this one is only used for household duties which definitely helps with it staying running!
Out of all my web sites and blog posts and projects over the years this is the one page that gets the most comments! I am glad it is of use to people (including myself as it turns out).