• Station Rear Accessory Test Cable
• Dummy Load (50 Ω, repeater wattage or higher) required for repeaters only
9.3.3
Verifying Receiver Circuitry Procedure
Procedure:
1 Connect equipment as shown in Figure 38: Test Equipment Setup for Verifying Receiver
Circuitry on page 83.
2 Set the Service Monitor to generate a 1.0 μV (-107 dBm) FM signal at the Receiver frequency,
modulated by a 1 kHz tone at 3 kHz deviation for 25 /30 kHz channel spacing, or 1.5 kHz
deviation for 12.5 kHz channel spacing. The 1 kHz tone should be audible through the external
speaker. If no audio is heard, suspect the following:
• Faulty Modem Module
• Faulty antenna-to-Receiver preselector RF cable (for the repeater with external metal
preselector)
• Faulty Service Monitor-to-station RF cable
• Faulty Antenna Relay (If installed)
• Faulty Preselector (If installed)
• Rear Panel to Modem Module cable unplugged
• Faulty rear panel to Modem Module Cable
3 If Audio is heard (the audio volume can be adjusted on the rear of the HSN1006), look at the
Oscilloscope window on the Aeroflex 3920 (or a separate O-Scope) and verify that the Audio
level Sine Wave measures between 0.75 to 1.5 Vpp. If not, connect to Tuner and increase the
RX Audio level until this is achieved. If the level cannot be obtained, suspect a faulty Modem.
4 Move the BNC cable from the Scope CH 1 input to the Audio 1 input.
5 Change System Monitor injection signal level to the noted levels in .
6 Measure the Receiver 12 dB SINAD sensitivity.
• If the SINAD level is less than 12 dB, suspect faulty Modem.
7 This completes the Verifying Receiver Circuitry test procedure. If all displays and measurements
are correct, the Receiver circuitry may be considered to be operating properly. Remove test
equipment, restore the repeater to normal service, and (if applicable) return to the
troubleshooting flow chart to resume troubleshooting sequence.
Chapter 9: SLR 5000 Series Performance Check or Testing
Motorola Solutions Confidential
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