Watkins-Johnson Company WJ-8718-19/FE Instruction Manual page 217

MAINTENANCE
WJ-8718-19/FE HF RECEIVER
5. Energize the receiver. Allow at least a 5 minute
warm-up to stabilize the circuits. (This assumes power
was not off more than 5 minutes to make the cable
connections.)
6. While observing the Counter display, adjust 2 MHz
Crystal Oscillator (U14) for a reading of 1.000000 MHz
+/- 3 Hz.
7. Deenergize the receiver and disconnect Digital Counter.
Replace A5A1A2 board into the proper slots.
4.3.6.2.6 BFO Synthesizer, A5A3, (791576) Alignment
Two alignments are required for the BFO Synthesizer (A5A3). Capacitor
C8 and resistor Rl are interdependent and must be aligned simultaneously.
1. Mount the BFO Synthesizer board on extender cards.
2. Adjust C8 until the closest reading to 3.0 Vdc is seen
at module pin 7.
3. Adjust Rl until the voltage difference between gate to
source of Q4 (Pins 3 and 2) is 0 Vdc. (The voltage
from gate to ground and from source to ground will be
approximately 1.2 Vdc.)
4. Adjust C8 again until the closer reading to 3.0 Vdc is
seen at module pin 7.
4.3.6.3 Receiver Alignment
4.3.6.3.1 Input Converter, A3, (791592) Alignment
1. Deenergize the receiver and loosen the two (2)
captivated screws holding the A3 module to the
chassis. Pull the A3 module out and remove its cover.
Connect test equipment as shown in Figure 4-2. Be
careful that Input Converter does not short to the
adjacent power supply circuitry.
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