HP 8560A

e. If the DVM reading is outside the range in step c but inside the range in step d, suspect
one of the filter-reactive components.
8. If the ALC loop is working correctly
(A4J9 pin 4 within the test tolerances given), then
either the output attenuator is defective, or A4U810 pin 6 (in ALC loop integrator) is
outside of its +3 to +6 Vdc range.
9. Reconnect W52 (coax 9) to A5J4.
300 Hz to 3 kHz Resolution Bandwidth Out of Specification
1. If the 3 dB bandwidth of one of these filters is incorrect, suspect a failure of one of the five
available sweeps from A4 Cal Oscillators sweep generator (function block .Z). These sweeps
are generated by changing the switch settings of A4U803 which routes signals through
A4U802 and A4U804.
2. Disconnect W52 (coax 9) from A4J8.
3. Connect the source connection of a 3 dB power splitter (Minicircuits Model: ZSC J-2-l)
to A4J8. Connect one output of the power splitter to the input of an HP 8566A/B
Spectrum Analyzer. Connect the other output of the power splitter to cable W52 (coax
9).
Note
If a 3 dB power splitter is not available, an SMB tee and an active probe
may be substituted. Connect the active probe between the tee and the other
spectrum analyzer. The absolute power levels are approximately 3
dB higher
than those stated below, due to the elimination of the 3 dB power splitter.
4. Press [INSTR PRESET) on the HP 8566A/B and set the controls as follows:
CENTER FREQUENCY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.8 MHz
SPAN
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 Hz
REFERENCE LEVEL
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -43
dBm
RESOLUTION BANDWIDTH
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
kHz
VIDEO BW
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10kHz
SWEEP TIME
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50ms
SCALE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ldB/DIV
SWEEP
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..SINGLE
5. On the spectrum analyzer, press (PRESET), (CAL).
6. Press FULL IF ADJ . When the display reads ADJUSTING IF: 10 kHz RBW, press (m) on
the HP 8566A/B.
7. The HP 8566A/B
screen illustrates frequency versus time of the A4 Cal Oscillator’s
output sweeps. See Figure 8-16. The slope of the HP 8566A/B 100 kHz resolution
bandwidth is used to detect frequency changes. Sweeps that vary (greater than 30%) from
the normal levels, trigger error code 581 or 582.
8. Press FULL IF ADJ . When the display reads ADJUSTING IF: 3 kHz, press (E) on the
HP 8566A/B.
9. Figure 8-17 illustrates normal operation. Severe failures (slope error greater than 30%)
and subtle 3
kHz resolution bandwidth errors (less than 30%) indicate a problem with
A4U802, A4U803, A4U804, or A4U106.
8-36 IF Section