HP 8560A, Service Manual

Page: 370 / 450

4. Measure the YTO frequency at the front-panel’s LO OUTPUT jack and record
below:
YTO Frequency (measured) = MHz
A l 4 F R E Q U E N C Y C O N T R O L A S S E M B L Y
M A I N C O I L T U N I N G
F M C O I L
TUNING I
I
T
I
I
I
SAMPLER
I - - -
ROLLER TEST
A P P R O X - 3 0
63 TO 105 5 MHz
M A I N R O L L E R F R E O
T O
63 TO 105 5 MHz
W H E N
A S M A I N R O L L E R F R E Q
S K 1 1 0 8
Figure 10-8. Troubleshooting an Unlocked YTO PLL
5. Calculate the frequency error by subtracting the frequency recorded in step 3 from
the frequency recorded in step 4. Record the result below:
YTO Frequency Error = MHz
YTO Frequency Error = YTO Frequency -YTO
On the HP press
MORE, FREQ DIAGNOSE,
and
MAIN ROLLER.
Record the Main
Roller frequency below:
Main Roller Frequency =
7. If the YTO Frequency Error recorded in step 5 is greater than 30 MHz, do the following:
a. Check the Adjustments using
the TAM or the procedure in Chapter 2.
b. Check the YTO using the procedure in steps 41 through 49 below, or using
Manual Probe Troubleshooting with the TAM on
and
c. Refer to steps 10 through 34 below.
Synthesizer Section