Model 5340A
Maintenance and Service
Figure 5
-
2. Adjustment Procedures (Continued)
6.
A8R13 ADJUSTMENT (LEVEL)
a.
Connect oscilloscope probe to XAll(1) (Mix sig 20 kHz). Set Channel A controls to
0.02
V/cm,
ac coupled.
Set SWEEP to 50
pdcm.
b. Set KO5 switch to LOCK and observe 20 kHz waveform.
c. Vary
KO5 VOLTAGE CONTROL
so
that the 5340A Display varies from 100 MHz to 185 MHz.
d. Adjust KO5 VOLTAGE CONTROL
so
150 MHz
is
displayed.
e. While continually flipping the
KO5 LOCK
-
UNLOCK switch, vary potentiometer A8R13 (LEVEL)
counterclockwise until scope waveform jumps from
20
kHz to 40 kHz.
f. Set the KO5 switch to LOCK. Vary potentiometer A8R13 clockwise until 20 kHz
is
again displayed.
g. Measure and record the voltage from the wiper of
A8R13 to ground (easily accessible without removing
A8)
___
volts.
h.
Add
10%
to the voltage obtained in step g.
___
volts
+
10%
=
~
volts.
i.
Adjust A8R13 until voltage on its wiper equals that calculated in step h.
j.
While constantly flipping the KO5 LOCK
-
UNLOCK switch, vary KO5 VOLTAGE CONTROL
so
that the
5340A display varies from 100 MHz to 185 MHz. Observe oscilloscope for
a
constant 20 kHz display. If
10
kHz, 30 kHz,
or
40 kHz appears on the scope at any time, readjust A8R13 clockwise
for
an additional
10% voltage.
k. Change oscilloscope SWEEP to 5
ps/cm.
1.
Observe the small transient (marker pulse) riding on the 20 kHz sine wave.
m. As
KO5 VOLTAGE CONTROL
is
varied for
a
5340A display of 100 MHz to 185 MHz, observe marker
pulse.
It
should not move more than
*5
ps
(1
cm).
7.
INPUT LOOP ADJUSTMENT
a.
Adjust KO5 for a 100 MHz display. Measure and record Feed
-
Forward
(FF)
signal, available at XA7(10).
Vl=.--.--.
b.
Adjust
KO5 for
a
150 MHz display. Measure and record
FF.
V2
=
___
.
c. Adjust KO5 for a 185 MHz display. Measure and record
FF.
V3
=
~.
d. Remove KO5 from XA7 and install A7.
Disconnect all other test connections.
e. Set oscilloscope controls:
CHANNEL A to 0.2
V/cm; DC coupled:
+
up
SYNC to INT,
t
slope, AC
MODE to NORM
SWEEP to 10
ms/cm
DISPLAY
to
CHANNEL A
f.
Adjust Channel A position
so
that zero volts is at the bottom graticule on the screen.
g. Using
1O:l
divider probes, connect Channel A to Feed
-
Forward
(FF)
signal available
at
XA7(10).
h. Set the 5340A RANGE switch to
10
Hz
-
18
GHz
and RESOLUTION switch to
100
Hz.
i. Set
A7R27 (GAIN) fully clockwise.
j.
Adjust A7R13 (BAL)
so
that the level
start
and end
of the waveform is at V2
measured in step b.
k. Adjust
A7R25 (AMP) and A5P15 (DC ADJ) until
excursion
of
the waveform
g
ed from V1 to V3.
See waveform shown at
rjgh
B
.
1.
Disconnect all test connections.
v3
-
v2
-
v1
-
ov
-
5
-
8
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