How to Set/Reset a Meridian 501 Control Unit

Archived from groups: rec.audio.high-end (More info?)

I have a second hand Meridian 501 Control Unit.
When I use it with a CD it works OK.
However, when I try the Radio or TV input it behaves very strangely.
When both Right and Left connections are made it plays only the Rright channel.
When a single connection (say Right or Left) is made it plays the Left channel.
I never encountered such a behavior until now.

Does this mean that I have to repair the unit?
Is there any way to reset it?

Thanks in advance for any useful suggestion.

Andrei