Sounds like a good deal. The weak volume is a problem that plagues many SE/30s these days, it is due to degredation of the capacitors on the motherboard. Both of my SE/30s have this problem, one quite a bit more than the other. There are various threads on these forums discussing repairs for these problems and even someone who is advertising replacement capacitor kits. If you fancy a bit of an electronic challenge the you could replace some of the caps, though if it is working alright at the moment I would just leave it be.