HP 83522A Service Notes page 239

Model 83522A Service
SWEPT AMPLITUDE
ANALYZER
SWEEP
OCSILLATOR
ATTENUATOR
Figure 8-26. Typical A LC Troubleshooting Setup
RPG/Power Display Failure
Check that the POWER display changes when either the RPG is rotated or data
is entered via the 8350A keyboard. This verifies that the digital information is
reaching the mainframe, is properly processed, and then displayed.
If the display is flashing rapidly or showing random patterns, refer to
A1/A2 Front Panel or A3 Digital Interface troubleshooting. If the RPG
causes a change in the measured RF power level, but the POWER display
remains the same, refer to A1/A2 troubleshooting. If the RPG produces no
response whatsoever, or if the front panel display is blank, refer to AlIA2
troubleshooting, and trace the problem back to the 8350A mainframe.
Unleveled (LED)
If the UNLEVELED light turns on during the sweep, enter a sweep time of 2.4
seconds (i.e. one second per GHz). Observe the SWP light on the 8350A Sweep
Oscillator, and determine at which times during the sweep the UNLEVELED
light turns on.
If the UNLEVELED light remains lit during retrace, suspect problems in
the front panel annunciator drivers. Refer to AlIA2 troubleshooting.
If the UNLEVELED light blinks briefly at the beginning of the sweep, the
plug-in may be sweeping through 0 Hz and causing an ALC drop-out.
Check this by slowly increasing the start frequency. If the UNLEVELED
light stops blinking, enter a CW frequency of 50 MHz and enable the 50
MHz crystal marker. Slowly adjust the 83522A front panel FREQ CAL
knob until the MKR light stays on. Press
INSTR PRESET
and observe
the UNLEVELED light. A frequency counter may be used to check
frequency accuracy at 10 MHz or 50 MHz. If necessary, refer to Section V,
Adjustments, in this manual, and perform the Frequency Accuracy
calibration procedure.
If the UNLEVELED light flashes briefly during the sweep, but does not
imply any of the above failure modes, check power flatness. See below.