Just received a used AVIC-F900BT and have it on my bench . I can play the radio or a CD and I can only hear it if I put my ear to the speaker with the volume control full up. Mute is off and mute lead is not touching anything. Any ideas???

Found my own mistake. The person I bought the radio from apparently used amplifiers on all his outputs and all the speaker wires were bundled up and taped closed. So I connected my speakers to the outputs that were left open - the ones that went to the amplifiers. Dumb mistake on my part.

Ron