Sansui AU-999 phono input is *extremely* quiet. What's wrong?

[PantherPTL]

Hello, I picked up an AU-999 / TU-99 pair at an Estate Sale this summer. I've paired these with my existing Technics SL-1300 turntable, which worked fine with my previous receiver from the '90s.

The Tuner sounds great. The auxiliary input sounds great from my an old iPod.

The problem is that the Phono 1 and Phono 2 inputs are extremely quiet when connected to the turntable. I usually listen to the tuner at "2" on the volume dial. Can't even hear the turntable at "2". When I turn the knob to "9" the turntable is playing at a listenable, but still quiet, volume. If I switch to the TU-999 at this volume I just about blow out the speakers.

Auxiliary input hooked up to the Phono ports sound fine and are at the correct volume.

The iPod playing on the Phono 2 port sounds perfect. The Phono 1 input, though, is scratchy and does not sound good.

Curious if you have any idea what could be going wrong with my AU-999?

 

[PantherPTL]

Any ideas?

 

[Hyperion]

Sounds like dirty switches - namely 'S1' Source Selector switch, DeOxit is your friend.

I have just noticed there is an output gain control on the output of the phono amplifier, VR601 and VR602 - it could be that someone has turned it right down. These are on the lower left of the rear panel and are called 'Level Adjust' - check that.

Note also that Phono inputs are VERY sensitive inputs so you should not normally be playing an iPod through them - use the 'AUX' or 'Tuner' input. You are getting away with it because someone has probably turned the Phono 2 'level adjust' down as well.