MP3 Cassette Solution

Step 4 Nearly done...

After the player was positioned thus...I did a test close. Bugger, the wafer thin battery wasn't 'wafer thin' after all. It had to be gently unstuck and laid to the right side of the shell. Connecting the audio out from the player to the audio in on the adapter is actually a cinch. After stripping back the 3.5mm headphone jack that came with the kit...it was plugged into the player as usual (removing one of the 2.5mm jacks in the cassette shell to make room). The wires were then soldered colour to colour on the remaining 2.5mm jack. This fed audio into the cassette adapter, and also back out the socket for testing. To charge the thing...another cut down USB adaptor. The kind you pick up from Woolworths that come in a set of 'keys' with a m/f cable.
The look on my co-workers faces the next day was priceless. For a cheap mp3 player it managed about four hours of playback before needing a charge. It certainly helped during the Sunday shift. For now though - it's back in the car for you mate.