Troubleshooting An Unlocked Yto Pll - HP 8560E Service Manual

Synthesizer Section
Unlocked YTO PLL

Troubleshooting an Unlocked YTO PLL

1. If the YTO PLL is unlocked, error code 301 should be displayed.
Place the HP 8560E/EC in zero span.
illustrates the simplified YTO PLL.
2. Move the jumper on A14J23 to connect pins 2 and 3 (TEST position).
Refer to Figure 10-3 on page 515
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 HP 8560E/EC, press
, and
DIAGNOSE LO FREQ
YTO frequency calculated. Record calculated frequency of the YTO
below:
YTO Frequency (calculated) = ________________________GHz
4. Measure the YTO frequency at the front panel 1ST LO OUTPUT
jack and record below:
YTO Frequency (measured) =________________________ GHz
540
Figure 10-7 on page 541
for the location of A14J23. Error
,
CAL MORE 1 OF 2
. The displayed LO FREQ is the desired
,
FREQ
Chapter 10