Is the output lead fixed, or does a 1210 have RCA connectors? If so, try changing the cable. If not, take the backs off the RCA connectors and check the solder joints haven't come adrift. Next, check the headshell wires, make sure all are secure. If these are OK, it could be arm wiring, which takes nerve and a steady hand. Changed the wiring in my Rega RB200 as the previous owner had pulled it out by accident. Very fiddly but not technically difficult.