My Magnavox Stereo Console from 1968 seems to have a problem with the left channel speakers. I no longer get sound from them. The right channel speakers work fine. I've checked the wiring in the back but cannot locate the problem. This particular model has the turntable on the left, radio on right. The tv which was in the center had been removed in 1995. The left channel spearkers worked great until about a week ago. Any suggestions on what might be the problem? Thanks.