Agilent Technologies 8564EC Service Manual page 403

Synthesizer Section
Confirming a Faulty Synthesizer Section
10.Set the spectrum analyzer to the following settings:
11.If the 1st LO is present, a signal should be displayed at about
Check A14 12.On the spectrum analyzer press
frequency
control assembly
(steps 12-18)
Fractional N Oscillator Frequency = _________________MHz
13.Check A14J304 (FRAC N TEST) port with a spectrum analyzer for
14.Disconnect W32 from A14J501 and connect the output of a signal
15.Set the signal source to the following settings:
16.Tune the source 1 kHz below the fractional N frequency. The voltage
530
Center frequency ........................................................ 300 MHz
Span ............................................................................ 100 MHz
−10 dBm (approximately ±20 MHz from the center frequency). If no
signal is displayed and ERR 338 LOMA AGC, ERR 339 SBTX AGC, or
ERR 340 SAMP AGC is not present, suspect the A7 LOMA. If no signal
is displayed and ERR 338 LOMA AGC, ERR 339 SBTX AGC, or ERR 340
SAMP AGC is present, check the A11 YTO as follows:
a. Set jumper A14J23 to the TEST position.
b. Set the spectrum analyzer to the following settings:
Center frequency ...................................................... 50 Hz
CF step ................................................................ 300 MHz
Span .............................................................................0Hz
c. Connect a power meter directly to the output of the A11 YTO.
d. Press the spectrum analyzer step-up key and measure the YTO
output power at each step.
e. Make sure that the A11 YTO output power is between +9 and
+13 dBm.
f. Set jumper A14J23 to the NORM position and reconnect the A11
YTO.
, ,
SPAN CAL MORE 1 OF 2
the fractional N oscillator frequency. (Ignore the minus sign, if
present.)
this exact frequency. The amplitude should be approximately
-10 dBm.
source to A14J501. Remove the jumper from A14J23. Connect the
positive lead of a DVM to A14J23 pin 1, and the negative lead to
A14J23 pin 3. See Figure 11-3 on page
Power ........................................................................... 0 dBm
Frequency .............................. Frequency recorded in step 12
measured on the DVM should be approximately 12 Vdc.
,
PRESET SPAN
, , and
FREQ DIAGNOSE
531.
,
ZERO
. Note
FRAC N FREQ
Chapter 11