Repair procedures, tests, and adjustments
80 Manpack Transceiver 2110 series Repair Guide
Adjusting the driver bias
To adjust the driver bias:
1 Switch off the transceiver.
1 Disconnect the exciter output from the PA by removing the RF drive between
connector J2 (Tx coaxial) on the PA & Filter PCB and connector J101 on the RF/IF
& Synthesiser PCB (see Figure 11 on page 30).
1 Set a multimeter to the DC low voltage range and connect it between the +12VSW
and DR test points on the PA & Filter PCB.
1 Switch on the transceiver.
1 Select any transmit channel and hold down PTT for at least 30 seconds.
1 Check that the voltage measures 160 mV ±10 mV.
If the current is out of the specified limit stated above, change it by adjusting DR
BIAS (R101) (see Figure 12 on page 30).
1 Release PTT on the handset.
1 Switch off the transceiver, disconnect the multimeter, then reconnect the RF drive
between connector J2 on the PA & Filter PCB and connector J101 on the RF/IF &
Synthesiser PCB.
1 Return to the Repair flowchart (see Figure 29 on page 95), if required.
Adjusting the PA bias
To adjust the bias of the PA output transistors:
1 Switch off the transceiver.
1 Disconnect the exciter output from the PA by removing the RF drive between
connector J2 (Tx coaxial) on the PA & Filter PCB and connector J101 on the RF/IF
& Synthesiser PCB (see Figure 11 on page 30).
1 De-solder the fuse F1–F2 next to the output transistors on the PA & Filter PCB (this
removes the DC supply to the output transistors V36 and V37) (see Figure 12 on
page 30).
1 Set a multimeter to DC 1 A range and connect it in place of the removed fuse
(positive nearest to transistors).
1 Switch on the transceiver.
PA & Filter PCB (08-06064-001) (see Figure 12 on page 30) and
RF/IF & Synthesiser PCB (08-06039-001) (see Figure 11 on page 30)
WARNING Do not short the multimeter leads to the chassis.
PA & Filter PCB (08-06064-001) (see Figure 12 on page 30) and
RF/IF & Synthesiser PCB (08-06039-001) (see Figure 11 on page 30)
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