You can probably try to fix that with some epoxy, the most obvious alternative is a new arm if that doesn't work. On the left channel cutting out, start at the cartridge and work your way backwards. Make sure the cartridge is good, and check everything back from there. Headshell leads, bayonet pins, the connections at the tonearm PCB (requires some disassembly), and the RCA plugs. These are pretty simple tables, just need a plan when you get into it. Another quick check is to reverse the turntable RCA leads at your amp/preamp. If the cut-out moves from the left channel to the right, then the problem is in the turntable. If if doesn't, the problem is in your phono stage.