Does the receiver have phono inputs? If not, that's the problem.
Analog playback issues
The other week my mom got out some of her records she had not played for several years. When she put one on it sounded garbled(like when you plug a cd player into the phono pre-amp on a receiver) the turntable is a technics sl dd24 from the mid or late 70's, and she assumed that it was just time to replace it with some budget table from Sony. When she set the new table up the same result occurred and she wound up returning the item. I'm fairly certain she had both the old and new turntable set up correctly. What could be the issue? Component info: Onkyo TX-8511 receiver, Technics sl dd24, Cartridge Technics P338