I bought a used JVC RX-509v stereo/surround receiver. I brought it home but I wasn't able to make it work. I plugged it into a speaker (they are the old fashioned wooden kind) but the music was very faint even with the volume cranked to the max.

I took it to the shop and they "repaired" it for me (and charged up the ass for it too) but my problem is the same. It doesn't matter what input I try...tape, video, aux, cd, they all sound very faint. Can anyone help?