HP 8560A - Troubleshooting an Unlocked YTO PLL

4. Measure the YTO frequency at the front-panel’s 1ST LO OUTPUT jack and record
below:
YTO Frequency (measured) = MHz
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I
’ Al4 FREQUENCY CONTROL ASSEMBLY /
!
MAIN COIL TUNING I
FM COIL
TUNING
I
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I
- T
I
I -
I
SAMPLER
I--- -s---
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J304
ROLLER TEST
APPROX -30 dBm
63 TO 105 5 MHz
MAIN ROLLER FREO
-15 TO OdBm
63 TO 105 5 MHz
WHEN
LOCKED,SAME
AS MAIN ROLLER FREQ
SK1 108
Figure 10-8. Troubleshooting an Unlocked YTO PLL
5. Calculate the YTO’s 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 (MEASURED) -YTO FreqUenCy(CALCuLATED)
6. On the HP 8560A, press MORE, FREQ DIAGNOSE, and MAIN ROLLER. Record the Main
Roller frequency below:
Main Roller Frequency = MHz
7. If the YTO Frequency Error recorded in step 5 is greater than 30 MHz, do the following:
a. Check the
YTO Adjustments using the TAM or the procedure in Chapter 2.
b. Check the YTO DACs using the procedure in steps 41 through 49 below, or using
Manual Probe Troubleshooting with the TAM on A14J17 and A14J18.
c. Refer to steps 10 through 34 below.
lo-26 Synthesizer Section