Your integrated does not have a phono stage (aka phono pre-amp) built in. As Uru975 says, the phono cart output (typically btween 0.1 and 5 millivolts) is much lower than line stage voltage (say from a cd player or tuner, typically about 1 - 2 volts) so it needs additional amplification (or gain) but it also needs equalization or modification of the frequency characteristics due to some engineering tricks performed during recording of LPs to improve performance due to some limitations of the medium. This is called the RIAA equalization, so even if you had enough gain, the sound would not be natural or satisfying.
The output from an external phono stage can be fed to any of the line level inputs on the intergated amp, regardless of how it's labeled. However, you should hear "something" if turn the volume way up. If you don't check to make sure that you have not engaged the tape monitor circuit (if there is one). If not, something else is wrong. BTW, a stand alone phono stage can be purchased new for as little as about $100. for used, look under pre-amps and then phono on Audiogon. You've not told us if you have a MM, MI, or MC cart. Low and perhaps moderate output MC (moving coil) carts require even more amplification than MI, MM or High Output MC carts and some pre-amps are built for them and have an MM/MC switch. You'll need to match that properly. What cart do you have?
