I would try to shield as much of the phono leads as possible.In some cases this may be as easy as replacing an unshielded wire with a properly shielded one or as difficult as trying to wrap delicate leads from your cartridge with shielding. It could also be the cartridge itself that is picking up the RF - try switching carts to see if the problem persists or changes.
Can you isolate the frequencies of the FM signal? On an active guitar pick-up system (a Gibson ES- Artist) that had RF issues I could even hear the program material (it was an AM religious station).
You may be able to do electronic shielding if you can identify the frequencies that are bleeding through, but an electronic filter may have an audible effect that is more pernicious than the original problem.
Can you isolate the frequencies of the FM signal? On an active guitar pick-up system (a Gibson ES- Artist) that had RF issues I could even hear the program material (it was an AM religious station).
You may be able to do electronic shielding if you can identify the frequencies that are bleeding through, but an electronic filter may have an audible effect that is more pernicious than the original problem.