Figure 4-7. Connector Pin-Out - High-Power Amplifier - Motorola ASTRO Digital Spectra Plus Detailed 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 in
September 5, 2008
Pin Configuration of J1 Pin Configuration of J1
As Viewed From Top of PA Board As Viewed From Top of PA Board
12 12 10 10
11 11 9 9
1 Control Voltage Limit 1 Control Voltage Limit
2 Control Voltage Drive 2 Control Voltage Drive
3 Current Sense + 3 Current Sense +
4 Key 9.4V 4 Key 9.4V
5 Filtered A+ 5 Filtered A+
6 Temp-Sense 6 Temp-Sense
7 Not Connected 7 Not Connected
8 Forward Power Detect 8 Forward Power Detect
9 9.6V 9 9.6V
10 Current Sense – 10 Current Sense –
11 Not Connected 11 Not Connected
12 Not Connected
Figure 4-7. Connector Pin-Out – High-Power Amplifier
Troubleshooting Procedures: Power Amplifier Procedures
Figure 4-7.
8 8 6 6 4 4 2 2
7 7 5 5 3 3 1 1
6881076C25-E