Finding Sony TA-AX8 Service Manual

When I play a vinyl with Sony TA-AX8 amplifier, the noise level is really high. I'm trying to find the service manual for it, in order to fix the problem.
I found several website provides manuals for Sony TA-AX series, but not include the TA-AX8 one.
Where would one pick up a service manual for Sony TA-AX8? Or could anyone provide the service manual?