‘KACHUNK’‘KACHUNK’In college in the late ‘60s I had a talent for fixing 8 Track carts. It made me some spare change in the dorm, and there was never a lack of work.
Note the difference, however. The Fidelpac cartridge that Muntz used has a big hole in the plastic case where your 8-track has a roller. That’s because the Fidelpac, which was used to play most every Radio and TV commercial and jingle until digital audio came along, worked that way - the pinch roller had to be brought up into position after the tape was inserted. The fancy way to do that like was with a solenoid, but that added cost, so the cheaper radio station machines, and the ones Muntz copied, used a lever that was operated by the finger. This made for an ugly appearance, with part of the mechanism exposed and Bill Lear had the inspiration to put the pinch roller inside, and thus the 8-track came to be. It solved that problem and because all you had to do was shove the tape into the machine, made them much nicer to look at and reasonably realiable. It was the tapes that became the aggravation...a fluttering strip of 1/4” tape alongside the road was a common sight!