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Model 5065A
Circuit Diagrams, Theory, and Maintenance
c.
Set unit controls:
1)
FUNCTION to LOOP OPEN OSC FREQ ADJ
FINE to 250. Connect oscilloscope vertical in
put to A8TP3. Connect oscilloscope horizontal
input to sweep test output A8TP2.
Set hori
zontal gain for a 5 cm sweep. Set vertical gain
to .5 V/cm.
2)
Adjust OSC FREQ ADJ COARSE until oscillo
scope pattern is similar to the
unadjusted
A8TP2 Output.
Display is indication that unit
is tuned near resonance.
d. When unit is tuned through resonance, oscillo
scope pattern changes from positive hump to a line (at
resonance center) then to a negative hump. Unit should
be adjusted for straight-line resonance indication be
tween humps.
e. Set OSC FREQ ADJ FINE to 200 (50 x 10'° fre
quency offset). Oscilloscope pattern should be similar
to the Optimized A8TP3 Output.
f.
Remove yellow wire from A7 Assembly. Check
phase detector zero with voltmeter at A8TP3.
Reading
should be 0 V -t 1 mV. If not, adjust A8R35.
TROUBLESHOOTING AND REPAIR
When any components are repaired or replaced the
assembly should be adjusted.
If Rubidium vapor as
sembly is replaced, phase detector circuits should be
readjusted.
For complete adjustment perform para
graphs 5-25, 5-27 through 5-30.
MODULE REPLACEMENT
Phase detector module may be replaced with power on.
After replacement new module should be adjusted per
paragraph 5-29.
Unadjusted A8TP3 Output
Optimized A8TP3 Output
Phase Detector Block Diagram
OSC FREQ ADJ
274 Hz
274 Hz
274 Hz
REFERENCE
OSCILLATOR
37 Hz
XTLTLTL
_T
SCHMITT
TRIGGER
FREQUENCY
Dl V'DER
I
I
TO
MULTIPLIER
ASSY A3
3 7 Hz
ERROR SIGNAL
FROM AC
AMP A7
DC ERROR
SIGNAL
TO OP AMP A9
» ■ TEST OUTPUT
SWEEP TEST
OUTPUT
8-45
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