HP 8562E Service Manual page 399

1. If the YTO PLL is unlocked, error code 301 should be displayed. Place the spectrum
analyzer in ZERO SPAN. Figure 11-7 illustrates the simplified YTO PLL.
2. Move the jumper on A14J23 to connect pins 2 and 3 (TEST position). Refer to
Figure 11-l for the location of A14J23. Error code 301 should no longer be displayed.
(The YTO PLL feedback path is now open and the YTO error voltage is forced to zero.)
3. On the spectrum analyzer, press (CAL), MORE i OF 2, FREB DTBCBISE , and LO FREI) .
The displayed LO FREQ is the desired YTO frequency calculated. Record the calculated
frequency of the YTO below:
4. Measure the YTO frequency at the front-panel First LO OUTPUT jack and record below:
I 1
Figure 1 l-7. Troubleshooting an Unlocked YTO PLL
YTO Frequency (calculated) =
YTO Frequency (measured) =
1
I
I
Synthesizer Section
MHz
MHz
1 l-25