MacAir sound board not detected; New cable fixes it.
The no sound problem was intermittent for a while and then just quit.
The repair was very straight forward and I got it done in about an hour.
Don't be afraid to try this yourself. The instructions were clear. The one thing I'd really suggest is to also get the small screw driver they suggest buying along with the cable and spudger. I had serveral screw drivers but only one marginally fit the types of screws in thte MacAir.