have you checked the fuzes on the motherboard\planner board\main board? there are a few that can blow and cuase some issues. check to see if sound is intergrated to motherboard if so it's not worth it, unless you have wiring diagram for sound and a scope for loss of signal\beat to identify the component cuasing the failure. good luck, be careful you can get a 50,000 volt shock if you touch the wrong area! no long tools made of metal and ground yourself.....!!
dj, November 2010