[R-390] R-390A calibrator oscillator

[John Saxon]

Good afternoon, gang:

This is John, K5ENQ, in Pearland, TX and I am working on a 390A to sell.  It is pretty much ready to go, but the 100KC calibrator has a "raspy" sound rather than a more "pure" sinusoidal sound.  This is the first 390A I have worked on, so I am new at this.

First, shouldn't the calibrator sound like a sine wave?  Nice clean sound?

I have attached a portion of the scope trace at pin 7 of the V205, the input to the cathode follower that delivers the signal to the 1st RF.  Should the signal be a pretty much pure square wave?  Note the rapid rise to zero at the beginning of the negative cycle.  All the resitances and voltages on the chart are fine with only one "funny" reading:  pin 7 of V205 on chart is -16.5 volts, I am getting -5.4.  Is that off enough to indicate a problem there?

Thanks,
John