We got two tape heads: one stereo reader head and one eraser head. The reader head as 4 pins, one set of 2 for left and for right. With a multimeter, we can check the resistance to find out which two pins are connected.
We then cut a 3.5mm audio jack connector in half and solder one half to each set of two pins on the tape. First, we have to remove the wires still connected:
To test the device, we dissect a casette and stick the tape to some paper:
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