Agilent Technologies E4406A VSA Series Service Manual page 41

Isolating an RF, Analog IF, Digital IF, Reference, Synthesizer, or CPU Problem
2. Toggle the Cal Switch before the 2nd Mixer by pressing
The remaining detailed checks require the A17 RF assembly to be
placed on an extender board (p/n E4406-60042). Turn the instrument
off before removing a PC board assembly from the instrument.
3. Turn the instrument on and wait for the CPU to boot and the Cal
4. Press
5. Refer to
NOTE
To view the 50 MHz internal calibrator signal (location I in
on the calibrated spectrum analyzer, press
If all the signal levels in the detailed troubleshooting section are correct
and the 21.4 MHz 2nd IF output signal measured on the calibrated
spectrum analyzer is incorrect, the most probable cause is the A17 RF
assembly.
NOTE
Note that these power levels are obtained using a 50Ω BNC to SMB
cable.
Chapter 1
Port IF Align IF Align Signal
, ,
Setup Res BW 20 kHz
, , ,
is functioning correctly, there should be ~10 comb teeth on the
instrument display at ~−40 dBm. These comb tooth signals come
from the Cal Oscillator on the A12 analog IF assembly and are
separated by ~468.5 kHz. If the comb teeth signal amplitudes are
correct, but a signal injected into the RF input is displayed at the
wrong amplitude, the failure is most likely caused from the RF input
connector up to the Cal Switch on the A17 RF assembly.Toggle the
input switch by pressing
MHz
. The power level with the internal calibrator switched in should
read −25 dBm on the instrument display. If this power level is
correct and the RF input signal from the external 50 MHz source is
displayed at the wrong amplitude, the AT1 7 dB pad, the RF input
connector, or the input switch on the A17 RF assembly may be
defective.
Diagnostics to run.
Preset Input Input Port
, ,
Figure 1-8 for the measurement locations.
Signal Type Comb
, ,
. If the Image Filter and following RF circuitry
Input Input Port 50 MHz Ref
, ,
RF Frequency 50 MHz
, ,
Input
Troubleshooting
Input Input
,
Span 5 MHz Meas
, , , ,
Frequency 50
, ,
.
Figure 1-8)
Input Port 50 MHz Ref
, ,
,
.
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