Replacement / alternative for contrast switch Hantarex MTC9000

[sollima]

I always have a reddisch glow when adjusting the colors. Lowering the Gain and Cut-off to the max still gives too much red in comparison to blue and green.
I replaced all the potmeters and transistors on the neck-card and the diodes and transistors on the mainboard of the red-circuit.

When adjusting the contrast switches I noticed when I turn the switches the other colors become brighter and dimmer except red.

I concluded that the red switch has gone bad.

I have trouble finding replacement switches. Can someone tell me what kind of switch it is? Or where I can order one?

Thank you in advance.