Lately I've been constantly buying vintage car stereos. Some have been fixed in the car and now I wonder how shall I do with the remaining loose units. Out of inspiration, I figure out a way to utilize them instead of letting it sit somewhere collecting dust. To cater for more units I need to add more channels on my homemade RCA selector switch.
I was going to suggest some blackout pics nice. Perhaps you could use one of these, 7-Position 28 Terminals Rotary Cam Selector / Changeover Switch, seven switch wafers, with seven detente positions, space for a few more head units