1970s Zenith All-in-one Stereo with record player issues

[Captainclock]

Hello everyone today I brought home a 1970s vintage Zenith AM/FM Stereo/Phono Table top Radio that also has Tape hookups on the back, and anyways its got a Zenith Badged BSR 3 Speed Turntable in it that for some reason the size adjustment switch (the switch that tells the tone arm which size of record is on the record player for the correct tonearm drop when using the changer) isn't working right, for some reason whenever you try to use the changer the tonearm drops at the 7" position even in spite of the size switch being set to 12" size which I've got the turntable out of the cabinet and I've looked it over and I really can't figure out why the turntable won't drop the tone arm at the right spot in reference to where the tonearm position switch is set. Anyone else on here have a similar issue with one of these old BSR Changers and if so what did you do to fix it?

Thanks for your Help.