Figure 4-7. Connector Pin-Out - High-Power Amplifier - Motorola ASTRO Digital Spectra Service Manual

4-48
Begin troubleshooting by connecting an RF power meter and appropriate power load to the antenna
connector. Connect the control cable and the power cable. Make sure the ignition sense lead is also
connected to the positive lead of the power supply. Note that a regulated DC power supply capable
of at least 30 A. is necessary to power a high-power Spectra transmitter. Remove the radio bottom
cover. Remove the PA shield by pulling straight up on the plastic handle. This must be done carefully,
as the edge of the PA shield can damage components on the PA board if it is removed unevenly. Set
the power supply to 13.4 V. The radio may now be turned on. All critical voltages may be measured
at connector J1 from the top side of the PA board. A diagram of the connector pin-out as viewed from
the top side of the PA board is shown below.
July 1, 2002
Pin Configuration of J1
As Viewed From Top of PA Board
12 10
11 9
1 Control Voltage Limit
2 Control Voltage Drive
3 Current Sense +
4 Key 9.4V
5 Filtered A+
6 Temp-Sense
7 Not Connected
8 Forward Power Detect
9 9.6V
10 Current Sense –
11 Not Connected

Figure 4-7. Connector Pin-Out - High-Power Amplifier

Troubleshooting Procedures: Power Amplifier Procedures
8 6 4 2
7 5 3 1
68P81076C25-C