The service manuel is very helpful, we where able to restore the device to its working operation again.
Text excerpt from page 4 (click to view)
5. Replacing switch in HD 7500 and HD 7501 START POSITION MID POSITION SWITCH HOLE IN HOUSING PART 25MM. END POSITION
HOUSING PART SMALL DETENT PIECE A MOVE THE SWITCH IN THIS DIRECTION
PRESS
PRESS IN THIS DIRECTION
6. Colour identification - Firstly determine your type of appliance (Column A) - Secondly determine the colourcode, which is printed on the typeplate of the appliance: HD 7500 /A /. /. is the colourcode - Determine also the coloursetting of the jug handle (Column B) - In the next columns you can read the original coloursetting of the other service parts.
A Type of appliance colourcode HD 7500 HD 7501 HD 7504 /2 /1 /1
A1 Type
B Jug handle (item 11)
C Jug lid (item 10)
D Jug cap (item 12) + spring orange orange
E Housing (item 3A)
F Filterholder + Cap (item 5) white/white ivory/ivory ivory/ivory
