Table 4-24. Power Control Dc Voltage Chart - Motorola ASTRO Digital Spectra Plus Service Manual

4-68
3. Apply the required input power via adapter cable 30-80373B27 or equivalent. For this
application, non N-type connectors are acceptable.
4. With the applied control voltage initially at 0 V slowly increase the voltage until power out
equals 17 Watts (15-Watt radio) or 38 Watts (38-Watt radio) Power should rise smoothly with
control voltage once the turn-on threshold is reached. Control voltage should no exceed
11.0 V.
5. If 11.0 V does not produce 17 (or 38) Watts, then a failure exists in the power amplifier circuit.
6. Refer to the voltage chart (see
within the limits shown in the chart, then a failure exists in the PA assembly.
7. If the voltages in the chart are correct, verify that the injection is at least 75 mW. (See the
VCO troubleshooting section.)
8. If no failure is located from the previous checks troubleshoot the power control circuitry.
RX MODE
LOCATION
LOW TYP
1 —
2
3
4 10.8 13.6
5 0
6 10.8 13.6
7
8 —
9
10 10.8 13.8
11 9.4
12 20.8 13.6
1 0
2
3 0
4
5
6 1.5
October 28, 2002
Table

Table 4-24. Power Control DC Voltage Chart

TX MODE
HI LOW TYP
— — — —
0 0 2.0
0 2.0 7.0
16.5 10.0 13.0
0 0 9.2 9.4
16.5 10.8 13.6
0 1.2
— — — —
0 1.3 3.5
16.5 10.8 13.6
9.6 9.9 9.4 9.6
16.5 10.0 13.0
0 0 0
0 3.2
0 0 0
0 0
0
3.0 4.5 1.5 3.0
Troubleshooting Procedures: Power Amplifier Procedures
4-24). Measure the indicated voltages. If they are not
HI
P0853
— Key (no pin or wire)
3.2 Control Voltage Limit
13.0 Drive Voltage
16.0
Current Sense +
9.8 Keyed 9.4
16.5 A+ to Command Board
Temp Sense (cutback begins at 3.3 V)
— Key (no pin)
6.0 Forward Detect Voltage
16.5 A+ to Command Board
9.9 9.6-V Supply from Command Board
Current Sense - (voltage delta 150 mV)
16.0
U0500
0 0 Ground
Control AMP Input
0 0
Control AMP Input (not used)
2 3.2 Control Voltage Limit (cutback at 3.3 V)
0 N.C.
4.5 Power Set from D-A (max power at 1.5 V)
COMMENTS
6881076C25-D