Motorola MTR2000 T5544 Instruction / Field Service Manual page 127

Note
68P81096E17-E
09/30/05
Verifying Transmitter Circuitry Procedure
1. Connect test equipment by performing Steps 1 to 5 shown in
Figure 6.
In the following steps, suspected faulty modules are ranked in order of
most to least likelihood.
2. Press the PTT button of the microphone and observe the PA Keyed
LED indicator (DSG5602) on the Station Control Module.
• If PA Keyed fails to light, suspect the following:
Faulty Power Amplifier Module
Faulty Exciter Module
Loose or bad Exciter-to-PA RF cable
Loose or bad PA-to-antenna RF output cable
Improperly terminated PA RF output cable
Faulty Station Control Module
Faulty Backplane
Faulty Antenna Relay
3. Measure output power by pressing the PTT button and observing
reading on in-line wattmeter.
• If PA output not at proper power (as set for particular site), adjust
the output power as described in the RSS online help.
4. If PA output power OK, set up R2001 or R2600 for spectrum analyzer
display. Press the PTT button and observe the display. The display
should show a single frequency carrier:
• If the display shows multiple carriers evenly spaced about the
carrier, suspect a faulty Exciter module or PA module.
• If the display shows a solid carrier but off frequency, suspect the
following:
Faulty Exciter or Station Control Module
Faulty external 5/10 MHz reference source (if used)
• If the display shows a single carrier moving erratically, suspect:
Faulty Station Control Module
Faulty Exciter Module
Troubleshooting
13