Chris_383,
If the RFI is something that has started lately and seems to have gotten worse the problem could be simply a corroded signal ground connection on an ic or even a signal ground pin connection on the cartridge. Try unplugging and plugging in the ics in the phono input jacks a few times and see if that helps. If the TT has phono jacks check them as well. Also check the connections on the cartridge
If the RFI is something that has started lately and seems to have gotten worse the problem could be simply a corroded signal ground connection on an ic or even a signal ground pin connection on the cartridge. Try unplugging and plugging in the ics in the phono input jacks a few times and see if that helps. If the TT has phono jacks check them as well. Also check the connections on the cartridge