Depends on which B-115 you are talking about. If this is a "vintage" '70s era B-115 then they were good but had a bunch of wires inside that had a tendency to come loose over time. Repairable but not easily diagnosed. Check Harmony Central for more info.
If this is the newer BA-115, then my guess is that it is something loose or disconnected inside. Mine had cabinet quality issues. If the amp is the BA-115 or BA-115T, then even a broken one for that much is a good deal, assuming you have a good repair shop nearby, as most amp repairs are usually round $100, so $220 for a BA-115 is a good price, period. Throw in a bass, better deal.
Ask a ton of questions and get some good pix. Oh, if this amp is not that old, LOUD may cover it under warranty still if its something in the Amp.