Audiophiles hifi appreciation thread old and new

Ok, another problem... Turntable not playing stereo, both speakers are fine (other inputs play fine) and both play fine in mono mode. I switched the sockets on the back round (as in connecting bits) and it changes which speaker doesn't work (when playing stereo one plays and one is dead).
Does that make any sense? Any idea what the problem could be? With my near ZERO knowledge of such things I would guess one of the two inputs from the turntable are dead hence why one speaker works?

Have you checked the earth? If turntable not earthed properly it will come out mono