My Beogram 8002 plays faint music out of one of the channels.  I confirmed that it is not the receiver or amplifier.  Is this likely to be a problem with the MMC cartridge or is there anything else that I should be checking?  Given the unique multi-pin plug, I'm not sure how to verify that the cable is properly functioning. Thanks for your help!

Probably the cartridge but I suppose it could be the muting circuit. The obvious way to test is to use a cartridge that you know is working but I guess one is not available. A continuity tester on the wiring would be one way.