VauWeh

I don't know this device, maybe the adjustment is similar to the 901, described here. Look for step 11, second picture. Make sure that the pin on the support of the circuit board is engaged in the guide rail on the knob (marked by the red rectangle in the second picture). If you turn the knob, the circuit board needs to be able to move up and down a bit, otherwise the machine will not work! Learn in step 12 how to adjust the speed.

Guter Hinweis! Sollte man auf jeden Fall verwenden.

Perhaps this helps, step 12.

Pues yo no sé la explicación. Es un miraculo. Hay teorias, puede leerlos más arriba.

Perhaps here?

I'm lucky I could help ! Greetings from Germany.

And? Was your fix successfull?

The pump is a Invensys CL4, now ARS CL4. (Google for it). What do you mean with “stronger"? It IS strong, making a pressure of about 16 bar, and more pressure does not make sense. If you want to have a change, try a ULKA EX4, but there will not be a great difference. Look for the right voltage.

If the pump does not work well, maybe its worth to carefully open it and clean it.

Vielleicht hier, kontrolliere genau!

Brewing piston - glas ball - spring - cover with screws. Pay attention to the spring: the thinner end shows towards the ball. The function of the ball is a “Aroma-Valve". The hot Coffee flows through the hole in the piston and has to bypass the spring-loaded ball, which therefore vibrates, thus producing the “crema".