6881076C25-E September 5, 2008
Troubleshooting Procedures: Power Amplifier Procedures 4-23
If it is verified that both power set and current limit are not related to the power problem, then the
synthesizer output must be checked. A milliwatt meter connected to the TX injection cable should
indicate at least 10 mW of injection power during key-up. If this is not the case, refer to the RF board
and VCO sections of this manual for troubleshooting procedures.
Table 4-8. Power Control DC Voltage Chart
LOCATION
RX MODE TX MODE
COMMENTS
LOW TYP HI LOW TYP HI
J1
1002.03.2
Control Voltage Limit
2 0 2.0 7.0 10.0
Drive Voltage
3 10.8 13.6 16.5 10.0 13.0 16.0
Current Sense +
40009.29.49.8
Keyed 9.4
5 10.8 13.6 16.5 10.0 13.0 16.0
A+ to Command Board
60 1.2
Temp Sense (cutback begins at 3.3-V)
7 ––––––
Key (no pin)
8 0 13.0 9.3 5.0
Forward Detect Voltage
9 10.8 13.6 16.5 10.0 13.0 16.0
A+ to Command Board
10
11
9.4
10.8
9.6
13.6
9.9
16.5
9.4
9.8
9.6
12.8
9.9
15.8
9.6-V Supply from Command Board
Current Sense – (voltage delta 150 mV)
12 ––––––
Key (no pin or wire)
U500
1000000
Ground
20 3.2
Control AMP Input
3000000
Control AMP Input (not used)
40023.2
Control Voltage Limit (cutback at 3.3 V)
59 0
N.C.
6 1.5 3.0 4.5 1.5 3.0 4.5
Power Set from D-A (max power at 1.5 V)
701.53.04.5
Power Set Buffer Out
801.33.56.0
Coupler Buffer Out
901.33.56.0
Forward Detect Volt
10 0 0
Reflected Power Detect (not used)
11 0 1.3 3.5 6.0
Same as pin 8 (not used)
12 0 0 1.2 6.0
Thermister Buffer out (increases as PA gets hot)
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