Over the last 30-odd years I have repaired literally thousands of audio products.  By mid 2004, I estimated that I had repaired over 5000 CD players alone.  Audio systems I have worked on include domestic Hi-Fi and Home Cinema, professional systems such as mixing consoles, Digital Audio Workstations and sound-reinforcement, through to highly specialised systems ranging from diagnostic audiometry, to complex IFE (In-Flight Entertainment) systems for several major international airlines.