Vintage Philips 900 Series Double Auto Reverse Cassette Tape Deck FC 911 | eBay
So here's the mechanism that started it all, the original Philips cassette recorder. This is a slightly later iteration with the speed regulator board but still the same chassis and layout. :
Philips N5151 Mark II Stereo cassette deck - Catawiki
Boxed Philips N2600 -2nd Car Cassette Player – historictech