Agilent Technologies HP 8719D Service Manual page 290

This is used in the "Analog Bus Correction Constants" adjustment as a
reference for calibrating the analog bus low and high resolution circuitry.
All Phase Lock
5. All Gnd
(Ground reference)
6. All Gnd
(Ground reference)
7. All Gnd
(Ground reference)
Swp Err
8. (Phase error voltage)
This node measures the voltage at the output of the phase comparator
on the All phase lock assembly. This error voltage corresponds to the
difference
in frequency between the divided IF and the 1 MHz reference frequency
from the Al2 assembly.
Figure 10-5. Node 8: Swp Err, Phase Error Voltage
9. 0.25V/GHz (Source oscillator tuning voltage)
This node displays the tuning voltage ramp used to tune the source
oscillators. You should see a voltage ramp like the one shown in Figure 10-5.
If this waveform is correct, you can be confident that the All phase lock
assembly, the source assemblies, the A13/A14 fractional-N assemblies, and
Service Key Menus and Error Messages