In this linked photo you can see a rolling "interference" through the display.
This only occurs when the //c is on, but not while just the Monitor //c is on.
It does appear to be more shaky and will distort the text characters on floppy read/write.
Is there a filter/capacitor/component that is responsible for this type of effect that I could replace? I don't know if it's relevant, but I do use one of these as my power supply for the //c