I'm trying to help a friend out with his Sebo C3.1...the slider control on the handle of the hose to adjust suction and to turn the vacuum off does not work. When you turn on the vacuum at the main unit with the slider at off, the vacuum turns on. Sliding the slider does not adjust the suction or power of the motor. without the hose connected, the vacuum turns on when pressing the power button. Any ideas? Does this sound like a problem in the hose or in the circuit board of the machine?