Looking for a source or the part name for these flat cables that connect the lever at the front panel of the amp to the switch at the lack of the amp (the blue flat cable on the photo). They seem tough to find.
Like many controls they would have been custom made for the OEM. If you need one for an old Pioneer, look for Pioneer parts. I don't think you will find them as generics. If you need 4PDT, I suppose it would be OK to find a tape twice as long as you need, and just loop it. I just don't remember if I could take them apart or not.
It's not a flex cable. It's a steel flat cable that slips inside that blue plastic.
The plastic is fixed at the front level and the PCB switch and the steel moves inside and so transfers the movement.
Perhaps You can replace it with a bicycle brake tube, if You can fix the cable somehow.
Assuming only the plastic is broken, align it and then a piece of wrap shrink tube would hold it.