Miele F53 fault

[Studioalley]

Hi everyone, my Miele W1712 recently always show up F53 fault, and the motor run faster than it should be. When in washing cycle, the drum should run in very slow speed, however it sometimes run in fast, which makes the machine shakes horrible. I searched on internet, which said F53 fault is the speed sensor. But I also read many people fixed the F53 fault by changing the motor carbon brushes. I am totally confused, how come carbon brushes issue is deal with the speed sensor problem. If the brushes is failed, motor should not run at all, why run faster? Can anyone give me some idea? Thanks a lot.

[Whitegoodshelp (Andy)]

I agree. If the motor is running fast check the tacho magnet on the motor. If it comes loose or breaks the PCB can’t control the motor. For more details about tacho coils and magnets check my article in Whitegoodshelp - 

This article is not specifically about Miele but should still be relevant if a tacho coil is fitted https://www.whitegoodshelp.co.uk/hoover-nextra-error-code-7/

[Studioalley]

Thanks Andy,  so I should check for the loose magnet, instead of changing the brushes.

 

[Whitegoodshelp (Andy)]

Yes. You wouldn’t replace carbon brushes without examining them anyway. If they look ok, are a decent size and not charred there can’t possibly be anything wrong with them. 

diagnosing carbon brushes 

Many motors don’t even have carbon brushes btw. 

[Studioalley]

Finally I repair the machine today. As I said before, the motor runs faster than it should be, however something it back to normal. Carbon brushes should not be the problem. After I disassembled the machine, the magnet for the tacho coil is perfectly normal, so the problem should be on the coil or connection. I found the socket for the tacho coil is not tight. Then I clean all connectors and re-clamp them. Now the machine so far works fine.
 

I also repaired the program selector on the tumble dryer. It was not working very well. It is a three pin on and off rotation switch. I re-solder the pins and clean it with alcohol. Problem fixed. 
 

In the tumble dryer I found an interesting parts. Two carbon brushes are contacting to the dryer drum. Anyone know what it is for?

[Studioalley]

Just found out, it is a moisture sensor contacts. 

[Whitegoodshelp (Andy)]

Sorry. I’ve been a bit busy over Christmas. Yes it’s how they detect the dryness or wetness of the laundry.