Possible solutions IF others do not solve it.
1. My tonearm wires come out of the arm above the base, and go into a RCA junction box for soldering.
I found one of my litz wires insulation had become bare and was touching the tonearm’s baseplate ONLY during a certain portion of the arms arc. Tiny damn wire, I put a tiny amount of liquid rubber on the wire at the place of contact, problem solved.
2. remove and verifty tightness (or replace) all headshell wires. at least rule it out, inspect the tonearm wires connections to their connectors.
3. deoxit, contact cleaner on din pins, rca jacks, preamp jacks, make/break/make connections several times, at least to rule it out.
4. exchange din cable or rca cables, again, to rule the cable out.