My Central Air Compressor is making a sound like it is arching (a loud electrical snap). I can't actually observe the arch and there is no indication where it is coming from. The Compressor is about 10 years old and has had no recent service to it.

I would get a tech in there to see what exactly is taking place. Hard to tell without opening the unit up and taking a look. If you feel comfortable doing this, just make sure all power to the unit is dead before opening it up, then stand back when you power it back up.