14: Maintenance
PRC1099A-MS
14-25
14.7.2
1650 kHz IF Board
Figure 14-8 below provides the component locations for adjustments and
signal input/output points. Table 14-5 summarizes the 1650 kHz IF board
adjustments.
14.7.3
Mixer Board
Table 14-6 provides a summary of Mixer board adjustments. Figure 14-9
provides signal input/output points and adjustments.
Table 14-5 1650 kHz IF Board Adjustments
Designator Adjustment
T1, T2, L1
Aligns the crystal filter for flattest passband response—factory set
for ±0.5 dB ripple in transmit mode.
T3, T4
Optimizes output in receive mode—factory set for maximum
output.
Figure 14-8 1650 kHz IF Board Adjustment Points
TX Passband
Adjust (T2)
TX Passband
Adjust (T1)
RX/TX
From Mixer Board
TX Input
From Audio Board
RX Output
To Audio Board
TX Passband
Adjust (L1)
RX Output
Adjust (T3)
RX Output
Adjust (T4)
Table 14-6 Mixer Board Adjustments
Designator Adjustment
C58
Optimizes 2nd LO. The 2nd LO output should be approximately
2.0 Vrms and monitored at the coaxial cable port.
The 1st LO output should be approxi7 to 10 dBm
monitored at TP1.
C53, T3
Sets the receiver output level—these adjustments are performed
at factory for maximum RX output.
