Miele S143 stick vacuum won't change speed?

[unconscious]

Hi guys!

I'm currently visiting my mum's new place and was just giving it a little clean with the S143 we got last year. Everything's been good the last few times I used it last week but for some reason since yesterday I cannot seem to change the suction from Min to Max. The slider works, you can hear a click on one of the switches inside of the handle, yet the speed changes the same - still on MIN as from the moment you turn it on.

I had a look inside, everything seems to be fine, the slider works ok, both of the switches seem to work. What do you reckon is the problem? Is this the max mode switch that would be faulty?

I've also start to notice after vacuuming for a bit longer that regardless of the mode I choose after a few minutes there seems to be a change in pitch of the vacuum. As if just for a minute the motor went into a slightly higher speed, but not yet enough for a MAX mode. Then it goes back to normal min mode. It happens every few minutes. ideas?

 

[relhall]

Normally I would guess the Electronic Unit is bad, though you mention that the switch is clicking once so I checked our demo unit. It clicks audibly twice - once for each speed.

I'm wondering if the doohickey that hits that second switch is not, for some reason.

I have not had one of these apart in some time so I don't have a visual to go off of, and the little drawings miele has are not clear, but if both switches are working ... I wonder if you can force it to high and have it stay, just to test theory.

Is it out of warranty?