Step 1: Materials
-A soldering iron
-Headphones or stereo wires and plugs
-A tape player
Step 2: Dissasemble the tape player
This step varies with the model of the tape player so I won`t put any picture.
Step 3: Locate the magnetic head
The head must have three wires, one is the ground and the two others are for the right and left channel.
Step 4: Locate where the magnetic head connects to the board
To identify what pin connects to each wire you can use your multimeter, by checking the continuity of the connections. I'ts usually represented by a diode in your multimeter.
Put a tip on where the wire connects to the head, then put the other tip in the connector. When it beeps the wire where you have put one tip connects to the point of the circuit where you have put the other.
Step 5: Solder the wires
Stereo wires usually have a copper shield that must be connected to ground, left channel its covered with a white or blue plastic and the right one is covered in blue.
Now you have to solder it where the magnetic head´s wires connects to the board.
If you can´t locate it you can solder it to the head.
The ground cable is usally covered in black plastic.
On mine ther was 2 points for the ground, that are short cicuited. That's why I only have connected the shield once.
If you crossed the right and left cables it will work fine too.