This is usually the type of thing caused by a stray wire or two shorting things out at the connection point. If this is temporary as you say, have you wired some speakers (like the Bose surrounds) into the HK recently?

If so (and even if not) check your connections very closely. It's likely that you have the stray wire thing going on. You might even want to re-do the connections entirely, just ot be sure.