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5-22
690XXB/691XXB MM
+24VH Supply Problems
This supply pr24 volts for the YIG-tuned oscillator heater,
YIG-tuned oscillator bias, the step attenuator and diplexer driver
circuits on the A9 PCB, the V/GHz circuit on the A12 PCB, and coarse,
fine, and YIG loop circuits. When the 690XXB/691XXB is switched to
OPERATE
, it also takes over the function of the 24VS supply and sup-
plies +24 volts to the 100 MHz reference oscillator oven heater, the
front panel LINE switch circuitry, and the optional 10 MHz high stabil-
ity time base oven heater.
Step 9.
Perform the following procedure to isolate malfunctions to
the +24VH supply and outlying load circuits.
a. Place the
LINE
switch to
STANDBY
.
b. Replace the A15 PCB assembly.
c.
Place the
LINE
switch to
OPERATE
and measure the
+24VH voltage per Table 5-7.
q
If the voltage is correct, the problem is cleared.
q
If the voltage is incorrect, go to step d.
d. Place the
LINE
switch to
STANDBY
.
e.
Remove the A4, A5, A7, A9, A12, and A14 PCBs and the
YIG-tuned oscillator assembly.
f.
Place the
LINE
switch to
OPERATE
and measure the
+24VH voltage.
q
If the voltage is correct, go to step g.
q
If the voltage is still incorrect, contact your local
Anritsu service center for assistance.
g. Place the
LINE
switch to
STANDBY
, then install one of
the removed PCBs or the YIG-tuned oscillator assembly.
h. Place the
LINE
switch to
OPERATE
and measure the
+24VH voltage.
i.
Continue steps g and h until the faulty PCB/assembly is
located.
Table 5-6.
Error Messages 105 and 106 (8 of 9)
TROUBLESHOOTING
TROUBLESHOOTING
TABLES
Summary of Contents for 680 C Series
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