Most probably it can be repaired.
There is a short circuit connection in the mixer somewhere that is causing the breaker to trip when the mixer’s switch is operated.
It could be a faulty component such as a capacitor being short circuit, an internal wire touching the frame of the mixer or maybe even the switch itself shorting out to the frame.
Here’s an image of the wiring for the mixer taken from the service manual. The manual has full dismantling instructions for the mixer starting on p.3.
With the mixer totally disconnected from the power, use a DMM’s (digital multimeter)-Ohmmeter function, in conjunction with the circuit diagram to test where the short circuit is in the mixer’s operating circuit.
Once you have identified the problem then if it is a component that is faulty the manual has a full parts list which will help in getting the replacement part or hopefully an equivalent part if it is not available.
If you don’t have a DMM or know how to use it or know how to read a circuit diagram then perhaps you may know someone who can do this for you.
If not then contact a reputable, professional electronics or appliance repair service and ask for a quote. Tell them about the service manual being available online as it will help them if they are unfamiliar with the mixer.
(click on image to enlarge for better viewing)
Hopefully this is of some help