A few years ago I purchased a Sony HTDDW1000 home theatre component package. Recently the receiver (a Sony STR-K1000P) went faulty so a few days ago I purchased a Onkyo TX-SR605. I realise that in the very near future I would need to replace the speakers so I wasn't too really worried about them. I got home and plugged it in and after a minute the Onkyo went in to protection mode.

I can't see what would cause this to happen. Before unplugging anything I confirmed that the connections were all ok. I checked the speakers are 6 ohm as is the default setting for the reciever. Any one able to offer any suggestions what likely may have caused this? Surely none of the connections should put it in to protection mode.