NGT—Checks and adjustments
NGT Transceiver System Technical Service Manual 173
Adjusting frequency
All the channels are synthesised and locked to the 44.545 MHz reference crystal
oscillator Z401.
To adjust the frequency:
1 Select test channel 30.
1 Remove the coaxial connector from J2 on the RF/IF PCB in the RF unit.
This disconnects the exciter output to the PA.
1 Connect a frequency counter to the exciter output J2 – Tx.
1 Hold down 3 to switch on the tune carrier.
1 Adjust trimmer C451 (drawing 08-05235) to a frequency of 29.9 MHz ±3Hz.
All the channels are synthesised and locked to the 14.848333 MHz reference crystal
oscillator Z1.
To adjust the frequency:
1 Select test channel 30.
1 Remove the coaxial connector from J2 on the RF/IF PCB in the RF unit.
This disconnects the exciter output to the PA.
1 Connect a frequency counter to the exciter output J2 – Tx.
1 Hold down 3 to switch on the tune carrier.
1 Adjust trimmer C7 (drawing 08-05963) to a frequency of 29.9 MHz ±3Hz.
ALTERNATIVE TEXT
Drawing 08-05261 (sheet 2)
NOTE
The transceiver must be in Service mode to make this adjustment (see
page 154, Accessing Service mode).
NOTE
Wait for at least five minutes after switching on the transceiver before
adjusting the frequency.
ALTERNATIVE TEXT
Drawing 08-05889 (sheet 2)
NOTE If the PCB issue status is -06 or earlier, see drawing 08-05889 (sheet 2).
NOTE
The transceiver must be in Service mode to perform this check (see
page 154, Accessing Service mode).
NOTE
Wait for at least five minutes after switching the transceiver on before
adjusting the frequency.
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