Sony Walkman

Problem:    Intermittent audio connection 
Solution:   Get a replacement 3.5mm  
Brand:  Sony 
Cost new:   ??? 
Cost of fix:    0p 
Age:    TODO 
Success?:   Yes 

The audio jack would only work if you pressed the audio jack in at a certain angle, so this was an obvious fix. Re-solder the connector and make sure it is making a good connection and not likely to pry off again.