The Journey - Part The Second

 The next castaway we picked up in the Journey was the SX-980. Another crusty, dirty piece of derelict flotsam we thought "salvageable".

This was also another pleasant encounter, and after delousing our new arrival, we proceeded to give them a physical, and return them to health. It required a session Under the Knife to restore it to health, having been afflicted with a failing trimmer capacitor.

The offending part is the small teardrop shaped item dead center in the picture.

The offending part was replaced with a proper air variable device, more suited to this application.

A forensic anakysis of the failed part revealed a crack through the ceramic dielectric, seen here as  a dark line at the six O'clock position.

Now that I had solid frequency setting for the Local Oscillator, I could move on to aligning the FM Multiplex section . Some of the adjustments were a bit off, and two of them, the "19kHz Notch Filter", and the Left/Right Stereo Separation controls, were way off. The Multiplex alignment was rewarded with a perfectly locked receiver to the Pilot Signal, as shown here with the Lissajous Figure.

It's not "Text Book Perfect", as one of the Sine wave components being fed to it has a prominent 76kHz sawtooth component riding on it.

Finishing the alignment resulted in a perfectly tracking dial. It's nice to tune to 88.9, and your station pops in perfectly clear, with the tuning meter dead center. I deviated slightly from the procedure when I set the FM Muting and Signal Strength Meter to be more useful in the Real World.

And this thing has a really "hot" tuner. It easily exceeds the Pioneer specs by 6~10dB, pulls in distant stations far better than the SX-780 did, and I wonder how it'll do when I get the outside FM antenna properly mounted in the Spring.

Adjusting and testing the Power Amplifier was a breeze. The DC Offset and Bias controls adjusted smoothly, and wound up being about dead center in their adjustment range. To adjust the "Power Output" meters, I fed it a specified signal, measured the voltage across the dummy load, and set the meter adjust to read what the actual power is into an 8 Ohm load. One thing I accidentally "discovered", was although this amp is rated 80 Watts per channel, it easily made 135 Watts, with no sign of clipping, when I accidentally drove the input too high. So at it's rated 80 Watts, it has a LOT of "Headroom".

In fact, the SX-980 had such good test results and "Qual Ratings", that it was promoted to Senior Chief of Operations, responsible for all audio switching and reproduction duties.

In its Quarters:

And so, The Journey continues......