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MAIN 1 t-NANCE
4.3.6.3.6
LED Intensity Adjustment
The intensity of the front panel Frequency Display can be varied by
potentiometer R2, which is located inside the front panel on the left side of the
Frequency Display LED's.
Turning R2 clockwise increases the LED intensity.
4.3.6.4
Frequency Extender Alignment
4.3.6.4.1
1st LO Synthesizer (FE-A1A1A1) (370689) Alignment
The only alignment points for the 1st LO Synthesizer are in the
VCO (FE-
A1A1A2) which is a very sensitive circuit; care must be taken to ensure proper
operation.
This procedure should be performed only when a definite alignment is
needed.
Table 4-41 lists the components and their parameters used in this procedure.
1.
Remove the Frequency Extender,
FE-A1,
from
the
receiver.
2.
Remove the cover plate to gain access to the 1st LO.
3.
Connect a Digital Voltmeter to terminal E5.
4.
Beginning at Band 0, align the 7 VCO Bands indicated in
Table 4-41.
Alignment is accomplished by monitoring the
voltage at pin Bl and adjusting the indicated components.
Note that L2, L3 and L4 will cause interaction between
the alignment of several bands.
5.
Check the 1st LO frequency band (test point E10 in the
VCO) while dialing the tuned frequency in 1 MHz steps
starting with 30.00000 MHz.
Table 4-41. VCO Alignment Parameters
VCO BAND
1ST LO FREQ
PIN Bl VOLTAGE
COMPONENT
0
190-199
-8.5
to
6.0
C6*, LI
1
200-209
-7.5
to
4.1
L2
2
210-219
-7.2
to
2.8
L3
3
220-229
-5.3
to
3.9
L2, L3
4
230-239
-6.6
to
2.7
L4
5
240-249
-6.0
to
2.2
L4, L2
6
250-259
-6.2
to
0.4
L3, L4
4-73
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