Step 1: Scoring a Nifty Lookin Hi-Fi
When buying your retro-stereo, try to have an idea in mind what you want to do with it, and make sure that the layout of your "antique" won't make your modifications impossible. My Hi-Fi originally had volume and tone knobs and a huge blank panel in-between where I'd eventually put the CD control buttons.
Have a vision . . . it'll make your life easier!
Step 2: Exploratory Surgery
I planned to integrate a Sony 5-disc changer that I no longer used, and spent the better part of an afternoon ripping it apart and figuring out how it worked. The first thing I realized was that I'd need to extend the ribbon cables connecting the display to the main control board. I'd also have to extend the ribbon cable connecting the control board to the changer carousel . . .