Beyond the list of standard restoration steps detailed on the main page, here are some added notes for this unit :

I acquired this receiver from a local collector and customer.  Exterior condition was very good.

The SX9000 was Pioneer’s flagship receiver in the early 70s and consequently included some unusual features

Tone Color : basically an additional equalizer stage with 4 preset boost settings for bass and treble (vivid, bass, flat and soft).  This is in addition to the normal bass, treble, loudness, high filter and low filter.  Tone Color “flat” passes the audio through without colorization (acts like a normal receiver).

Reverb : old school mechanical implementation (using springs) in a sealed metal housing mounted on 4 rubber posts to allow the assembly to vibrate

Source level : disc on back of the volume knob, this is a very handy variable muting that allows very fine sound level adjustments (using the entire range of the volume knob) at any decibel level.

High number of inputs : 2 phono, 2 aux, 2 tape decks, 2 microphones

After switch/pot cleaning, initial testing showed a high level of functionality.   FM reception, sound very good.

Recap went smoothly and found some issues:

     1 of the 4 original output transistors was bad so replaced all 4 with modern equivalents (see photo).

     FM stereo light always on (fixed, bad transistor)

     FM muting not working (fixed, add pull-down resistor)

     FM tuning meter sticking (fixed, acquired/installed replacement)

     Reverb too sensitive to vibrations/tapping on chassis (fixed, adjusted compression on the 4 rubber standoffs for the reverb unit)

Functional testing complete/passed. 

I find this to be a really nice sounding cap-coupled receiver.  The FM section is quite good with excellent sensitivity and sound qualities.  Many reviewers list the SX9000 one of the best vintage receivers of the era.

The complex audio path (due to adding the reverb and tone color amplifier stages) raises the hiss level a bit.  I did what I could to minimize this, but it still may be an issue for someone using headphones (especially in “vivid” mode with treble turned up).  It is not noticeable when using my test speakers (EPI M50s).

The cosmetics are excellent (see photos).  This is a really fine example inside and out.