Watkins-Johnson Company WJ-8718-19/FE Instruction Manual page 213

MAINTENANCE WJ-8718-19/FE HF RECEIVER
4.3.6.2.2 2nd LO Synthesizer, A5A2, (791601) Alignment
The 2nd LO Synthesizer procedure consists of a 32 MHz Loop Alignment
a Programmable Loop Alignment, and an Output Loop Alignment. Perform the
procedure in the given sequence.
CAUTION
For optimum results, the 2nd LO Synthesizer
Alignment should be performed in an ambient
temperature of +25° C +/- 5° C.
1. Preliminary Setup
a. Remove the top protective cover from the receiver.
b. Mount the 2nd LO Synthesizer board (A5A2) on an
extender card.
c. Energize the receiver and allow 30 minutes
warm-up time.
d. Using a Digital Voltmeter, verify that +15 Vdc +/-
0.25 Vdc is present at pins B5, B41, and A59, and
that +5 Vdc +/-0.25 Vdc is present at pins Al, Bl,
and B45.
e. Using a Frequency Counter, verify that the 1 MHz
reference frequency at pin B49 is 1.000000 MHz
and that the 10 kHz reference frequency at
pin A57 is 10.000 kHz.
NOTE
If the two reference frequencies are not
correct, perform the Time Base Adjustment
Procedure before proceeding with the 2nd LO
Synthesizer Alignment.
2. 32 MHz Loop Alignment
a. Connect the Digital Voltmeter to test point El.
b. Adjust capacitor C51 until a Voltmeter reading of
+3.0 Vdc is observed with the alignment tool
withdrawn from the VCO shield.
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