Channels bleeding into each other

Erik and Elizabeth thank you both for your insights. I had purchased this a few years ago with the idea of having it restored, it’s actually in pretty nice shape for its age. I was fiddling around with it recently and came across the crosstalk. Will hook it up again and give it a re-listen. Again thanks much. Dave

Technical term is "crosstalk." 

Turning the balance all the way to the left or right is not how to tell. :) The balance control is not meant to go all the way to off, but to give you a range of adjustment for recordings, hearing, and situations when equal loudness is not ideal. 

Crosstalk is usually very difficult to avoid it completely in stereo components. Even very good stereo components will not be perfectly free of crosstalk, and when measured may be -60 to -90 dB. 

Best,

E