HP 8753E - Page 411

Node 30
FN VC0 Det (Al4 VC0 detector)
See whether the F’N VCO is oscillating. The trace should resemble Figure 10-18.
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Figure 10-18. Analog Bus Node 30
Node 31
Count Gate (analog bus counter gate)
You should see a flat line at + 5 V across the operating frequency range. The
counter gate activity occurs during bandswitches, and therefore is not visible
on the analog bus. To view the bandswitch activity, @ok at..$is node on an
. . . . . . . . . . . . . . . . . . . . .
oscilloscope, using ~~~~~~~~. Refer to ~~~~~~~~~.-~~~~~~ mder the Analog
. . . . . .L......... . . . . . . . ..L . . . ..A .A? . . . . ..w................ .,.,,.. A.A...
:.:.:,.;: ,.,. i .,.,.,.,.,.~.,.,.,.,.,.~.,. i ,.,.,.~....... i . . . . . . n . . . . . _ _ _ _,,.,.,.,.,.,.,.,.,.,,/._i
Bus Menu heading.
Service Key Menus and Error Messages
1045