Diagnosis Help: Left channel out, turntable ground leads crossed somewhere

Ok, then I’m going to try changing out the RCA cable and resoldering the tonearm cables to see if that fixes the problem. 

Yes, it's more than a problem, it makes balanced drive impossible.  But the symptom is not hum; it's left channel dropout, which suggests an intermittent problem in the hot side of the L channel.  Since it is intermittent, such problems are often difficult to isolate, and the finding of continuity with a tester can be misleading.

lewm

The grounds business is a red herring, IMO.

If you're using a true balanced phono stage, a common ground is a major problem.

The grounds business is a red herring, IMO.

bobelton

I used the continuity tester and it beeps when I touch the two rca  outer shields ...

That is not normal. If a cartridge is installed, disconnect the cartridge and test it for continuity between the two grounds. There should be none. Either the cart is bad or the pickup arm wiring is bad.

I used the continuity tester and it beeps when ... I touch either of the green or blue cartridge lead spots with either of the rca cable outer grounding shells. 

That's normal.

Yeah I mean continuity. And no the tonearm wasn’t connected to a phono stage when I checked it. I used the continuity tester and it beeps when I touch the two rca  outer shields and when I touch either of the green or blue cartridge lead spots with either of the rca cable outer grounding shells. 

It isn't clear what you mean when you say you measured crosstalk. Do you mean continuity?

Was the tonearm connected to a phono stage when you determined gthat the grounds are in contact? If so, that’s normal. I think you need to look elsewhere for your intermittent L channel problem.