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Model 5065A
Circuit Diagrams, Theory, and Maintenance
WARNING
WHEN THE CHASSIS BOTTOM IS EXPOSED,
AVOID CONTACT WITH THE LINE TRANS
FORMER TERMINALS AT THE REAR OF THE
CHASSIS.
Faults may be isolated to the digital section or the
phase-locked-oscillator section by using the table.
Connect a Period Counter to A1TP1 and adjust the
thumbwheel switch as indicated in the table (Note
original setting before changing thumbwheels).
The
output signal from the digital divider should have the
period shown. If the period measurements are correct,
set thumbwheel switch back to original setting and
troubleshoot phase-locked-oscillator section. If periods
are incorrect, then throubleshoot digital section. Note:
If Y1 or associated components are suspected of failure
see Paragraph entitled "A1Y1, A1L1, A1L2, A1L3, or
A1L4 Check and Replacement."
MODULE REPLACEMENT
When Synthesizer Assembly A1 is replaced, the following
adjustment is necessary:
a. Set TIME
SCALE thumbwheel
and
HI/LO
switches for the same settings as the replaced Synthe
sizer Assembly.
b. Set instrument to normal operation
(CON
TINUOUS OPERATION light on).
c. Set front panel OSC FREQ ADJ FINE con
trol to 250.
d.
Set CIRCUIT CHECK meter to CONTROL.
Observing the meter indication, adjust OSC FREQ ADJ
COARSE control for a zero reading.
e. Set FUNCTION switch to LOOP OPEN.
f.
Set OSC FREQ ADJ FINE control to 200.
g.
Remove instrument top cover.
Connect the
vertical input of an oscilloscope to A8TP3 and the hori
zontal input to A8TP2.
h. Adjust oscilloscope for a pattern similar to the
following waveform.
Optimized A8TP3 Output
'i
8-12
Synthesizer A1TP1 Output Period (vs. Thumbwheel
Switch Setting) Table
Time Scale Thumbwheel
Setting
0000
0001
0002
0003
0004
0005
0006
0007
0008
0009
0010
0020
0030
0040
0050
0060
0070
0080
0090
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
2000
3000
4000
5000
6000
7000
8000
9000
Signal Period at
A1TP1 (jusec)
2,000.0
1,999.8
1,999.6
1,999.4
1,999.2
1,999.0
1,998.8
1,998.6
1,998.4
1,998.2
1,998.0
1,996.0
1,994.0
1,992.0
1,990.0
1,988.0
1,986.0
1,984.0
1,982.0
1,980.0
1,960.0
1,940.0
1,920.0
1,900.0
1,880.0
1,860.0
1,840.0
1,820.0
1,800.0
1,600.0
1,400.0
1,200.0
1,000.0
800.0
600.0
400.0
200.0
i. Adjust A3R3 fully ccw. The oscilloscope pattern
will disappear. Then adjust this control cw and as the
pattern appears, adjust cw until the pattern just splits. —
Then back off slightly to where the pattern is similar to
the optimized A8TP2 waveform.
j .
Remove oscilloscope connections and replace
top covers. Set OSC FREQ ADJ FINE to 250 and set
FUNCTION switch to OPER.
k.
Press LOGIC RESET pushbutton.
CONTINU- ~
OUS OPERATION light will come on and stay on.
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