Hello, I have a problem :)

Here is what it is:
Pioneer PL10 turntable with Empire 3000e cartridge (is that good? I'm new) hooked up to a Yamaha CR-640 with Polk 5jr+'s.

Only one channel works on the record player. The last TT I used was a Stanton STR-8 20 and when I plugged it back in it worked just fine. I lifted the cover and checked but I could see anything wrong with the wiring. When I put my fingers around the RCA cable that doesnt produce music, I get a humming noise.

What could be wrong?

When you switch the RCA channels does the dead channel also switch? If it does, then the problem is in the RCA and you will need to replace it. If the dead channel doesn't switch, than the cartridge may have a bad connection, or a bad coil. First clean the stylus with stylus cleaner, and clean the cartridge leads by removing each lead and cleaning with a contact cleaner such as Caig Progold. If the channel is still dead, buy or borrow a cartridge and see if that fixes the problem. A less likely cause of the problem is that one or more of the leads is bad. You can determine if that is the case by testing the continuity of each lead at the cartridge connector to the RCA's as follows:

Continuity Test: Disconnect the cartridge tags from the cartridge. With an ohm meter on it's lowest scale, check to insure that all desired internal tonearm and cable continuities exist and are no more than about two ohms, as follows: Left channel RCA plug positive (pin) is continuous to the White cartridge tag (upper left headshell pin).
Left channel RCA plug negative (sleeve) is continuous to the Blue cartridge tag (lower left headshell pin).
Right channel RCA plug positive (pin) is continuous to the Red cartridge tag (upper right headshell pin).
Right channel RCA plug negative (sleeve) is continuous to the Green cartridge tag (lower right headshell pin).

Good Luck!

Thanks for the advice Mark B.

I opened everything and checked, and all the wires look connected, although there is a slight bulge in the RCA jack where it is going into the inside of the TT. I grabbed my previous AudioTechnica cartridge and it did exactly the same thing as well.

I also switched the RCA cables around and the channels immediately reversed, in other words the right RCA was moved to the left input, and instead of hearing right only after reversing the plugs the speakers reversed as well. The RCA plug must be dead.

The RCA plug is soldered. I have never soldered before. Would it be stupid to try it out on my Turn Table?

EDIT: With headphones on there is absolutely no input sound, even noise, from the "dead" channel. It hums when my fingers get close to the plug.