Just got my old Rev.E iMac logicboard booting, but i'm stumped as to why the sound isn't working. All I get is a farting/buzzing sound from the speakers that changes pitch a bit when drives spin up and the CPU is doing stuff (from the PSU being loaded down a bit i'm guessing). I got nothing from the line out on the side of the board (assuming it will drive headphones...).
Any ideas? Have I cooked the sound chip? (there isn't any "Audio" section in system profiler which has me a little worried). Or have I missed hooking power up to something?.