Quickmill 05000A - Motor of the mill hums

Hello everybody!

First of all, I think it's great that this forum exists and also exotic machines like the Quickmill fully automatic machines are treated here by you. I am currently in the process of making a Quickmill Acquaviva 05000A from 1994 (hopefully) fit again.
Mechanically, after a gasket replacement and various new valves, the machine is almost ready for the next few years.

However, there is one problem that I have not been able to solve so far:
When switching on the machine, the motor of the mill is constantly under a slight voltage (measured around 5V), which causes a humming noise
.
Because of this, the old connection cables were already badly worn and the sheathing was brittle.Even with new wiring, the problem persists.

In the course of troubleshooting I replaced all optocouplers, triacs and thyristors on the board, unfortunately without the hoped for success. The diodes for the motor control still work. Would you have an idea where I could look further?
Unfortunately I didn't find a schematic for this board, but maybe someone knows this version of the control electronics.

I would be very happy about your answers.

David

QUOTE (Dastas @ Sunday, 21. February 2021, 00:18 Uhr)

Hello all! First of all, I think it's great that this forum exists and also exotic machines like the Quickmill fully automatic machines are covered here by you guys. I am currently working on the (hopefully) restoration of a 1994 Quickmill Acquaviva 05000A .Mechanically, after a gasket replacement and several new valves, the machine is almost ready for the coming years. However, there is one problem that I have not been able to solve so far: When turning on the machine, the mill's motor is constantly under a slight voltage (measured around 5V), which causes a humming sound</br>. As a result, the old connecting cables were already very worn and the sheathing was brittle. Even with new wiring, the problem persists. In the course of troubleshooting I replaced all optocouplers, triacs and thyristors on the circuit board, unfortunately without the hoped-for success. The diodes for the motor control are still working. Do you have an idea where I can look further? Unfortunately I have not found a schematic for this circuit board, but maybe someone knows this version of the control electronics. I would be very happy with your answers. David </br></br></br></br></br></br></br></br></br></br></br></br>

Hello,

In an old thread on koffiemachines.org I found your contribution about the mill of the QuickMill that keeps humming.

I have the same problem.

Did you still manage to fix this problem, and can you tell me how?

Thank you in advance.

Riens Middelhof