Troubleshooting the Transmit (TX) Path for Non-Simulcast Subsystems

Prerequisites:

The following equipment is required:

When and where to use:

This procedure is used to troubleshoot issues with the voting transmit path, including: Symptoms include: Transmitters are not keying at all, keyed but not hearing voice, or keyed but voice has intermittent quality issues, or station dekeys during a call.

Procedure:

  1. Determine if the STT signal is generated though the GTR 8000 to the MLC 8000 Subsite Link Converter Port 4.
  2. Determine if the input is calibrated in MLC 8000 Subsite Link Converter Ports 1–4, depending on the number of base radios.
    • If Yes, then continue to the next step.
    • If No, then calibrate the input using the input calibration method for STT. Verify that Input Level Differential (dB) is set correctly before calibration on the BR advanced configuration window in the MLC 8000 Configuration Tool.
  3. Look at the TX lines for activity using a service monitor.
    • If audio is not present on the TX lines, then continue to the next step.
    • If audio is present on the TX lines, then see Troubleshooting General Transmit and Infrastructure for the GTR 8000. Observe where the PA LED is illuminated on key up attempts, look at the status panel screen on the CSS to see if the transmitter is active or not, and so on.
  4. If the Port LED (ports 1 - 4) of the MLC 8000 Subsite Link Converter is Red, then try to isolate the problem. The Red LED indicates a problem in the link from the base radio to the MLC 8000 Subsite Link Converter in the MLC 8000 Subsite Link Converter Rx direction. This problem occurs when MLC 8000 Subsite Link Converter does not receive a status tone from the base radio for a time specified by the Status Tone Timeout (sec) field of the MLC 8000 Configuration Tool (the default is 60 seconds).
    1. Verify the configuration of the MLC 8000 Subsite Link Converter as follows:
      • Input Level Differential is configured properly
      • Status Tone Timeout (sec) is not configured to a too short value
    2. If you check the configuration and fix it and problem still occurs, then recalibrate the device.
    3. At the base radio, make sure that the base radio is powered on and generating status tone/ALMT. Connect to the base radio using a scope or multi-meter.
    4. Check the cable between the MLC 8000 Subsite Link Converter and base radio in both directions.
    5. If the problem still occurs, then contact Motorola Solutions.
  5. Check that the Comm LED is green.
    • If Yes, then continue to the next step.
    • If No, the LED is RED, then continue troubleshooting:
    If… Then…
    MLC 8000 Subsite Link Converter  
    Is the Comm LED on the MLC 8000 Subsite Link Converter RED? The link to one comparator or more has failed.
    Is the MLC 8000 Subsite Link Converter in the MLC 8000 Analog Comparator list?

    If Yes, then continue to the next step.

    If No, then add the MLC 8000 Subsite Link Converter to the voter list.
    The connection to the IP network is lost. Can you ping the MLC 8000 Subsite Link Converter from the MLC 8000 Analog Comparator?

    If Yes, then continue to the next step.

    If No, then troubleshoot the network connection. Contact Motorola Solutions Support Center (SSC) for issues with the configurations for the transport devices (routers and switches).
    MLC 8000 Analog Comparator  
    The connection to the IP network is lost. Can you ping the MLC 8000 Analog Comparator from the MLC 8000 Subsite Link Converter?

    If Yes, then continue to the next step.

    If No, then troubleshoot the network connection. Contact Motorola Solutions Support Center (SSC) for issues with the configurations for the transport devices (routers and switches).
    The link to one or more base radio has failed (either the MLC 8000 Subsite Link Converter is not responding to keep alive messages of the MLC 8000 Analog Comparator or the MLC 8000 Subsite Link Converter reports that it lost connection to the base radio). This issue might be either a problem of the IP network or a network cable should be checked (or replaced).
    One of the associated MLC 8000 Subsite Link Converters is going through a reset or a power outage has occurred.

    1. Wait several minutes to see if the LED returns to green, which occurs when the MLC 8000 Subsite Link Converter has recovered its connection.

    2. If after several minutes the COMM LED stays red, then pull the log file from the device to determine which MLC 8000 Subsite Link Converter has lost connection. Check the state of this MLC 8000 Subsite Link Converter – if it is indeed undergoing a power outage, then it will recover shortly.
  6. Check that the R2 LED on the MLC 8000 Subsite Link Converter is green.
    • If Yes, then continue to the next step.
    • If No, then continue troubleshooting:

    If… Then…
    Is the MLC 8000 Subsite Link Converter configured as IP Simulcast type in the MLC 8000 Configuration Tool?

    If Yes, then continue to the next step.

    If No, then configure the cluster as IP Simulcast.
  7. Problems with MLC 8000 Subsite Link Converter Tx are discovered at the base radio side when ALMT from the MLC 8000 Subsite Link Converter is either not transmitted at all or transmitted in low quality or in low power. The corresponding Port LED at the MLC 8000 Subsite Link Converter may or may not be green (meaning that the MLC 8000 Subsite Link Converter may not be aware of this problem).
    1. Check that the MLC 8000 Subsite Link Converter outputs ALMT (this is done by scope or multi-meter). The gain of the transmitted ALMT should be in a proper gain (for example, -10 dB).
    2. If that does not help, then check that the dual gain amplifier (output direction and input direction) in the MLC 8000 Subsite Link Converter are configured properly.
    3. CODEC gain (as indicated by the sliders in the BR Audio Monitoring and Calibration window of the MLC 8000 Configuration Tool).
    4. If that does not help, determine whether there is no Tx in console-generated audio or in subscriber-generated audio or in both.
      CautionAnalog Link Monitor Tone (ALMT) is only supported on Conventional Mixed Mode channels with the V.24 interface. It is not supported on Conventional Mixed Mode channels with the Ethernet interface and is not supported on analog conventional channels.
  8. Check that the MLC 8000 Subsite Link Converter is connected though port 4 (4-wire) to the base radio.
    • If Yes, then continue to the next step.
    • If No, then connect the MLC 8000 Subsite Link Converter port 4 (4-wire) to the base radio using proper cables and punch block if needed.
  9. Determine if the MLC 8000 Subsite Link Converter is configured as Tx\Rx or Tx only on the MLC 8000 Analog Comparator list.
    • If Yes, then continue to the next step.
    • If No, then configure the MLC 8000 Subsite Link Converter as Tx\Rx or Tx Only in the MLC 8000 Configuration Tool.
  10. For tone remote (TRC), ensure that the link is correct for the Tx path.
  11. For tone remote (TRC), if transmitting to the console with a TRC tone, the tone is distorted if too large in the MLC 8000 Analog Comparator. Recalibrate the input value on Port 1.
  12. Using the wiring scheme and a multi-meter, verify all the pins from RJ45 to GTR 8000 Base Radio are correct.
  13. Determine if the system was calibrated.
    • If Yes, then continue to the next step.
    • If No, then recalibrate the system (time offset and gains).
  14. If calibration fails after you made hardware changes, perform these steps.
    NoteIf the Port LED (1–4) illuminates RED and then turns off, and you have made hardware changes, you have to perform calibration. This situation applies if hardware has been replaced (such as cables, base radios, MLC 8000 Subsite Link Converters, or MLC 8000 Analog Comparators).
    1. Select the MLC 8000 Analog Comparator to calibrate by clicking it in the channel cluster tree. Click the Audio Monitoring button or right-click the MLC 8000 Subsite Link Converter and then click Audio Monitoring and Calibration.
    2. Verify that there is an STT/ALMT signal from the base radio and press the Calibrate button. If a success message appears, the calibration process is done. In case of a failure message, go to the next step.
    3. Select the Input From Radio/Console radio button and click Start.
    4. If no signal displays in the Audio Monitoring and Calibration window, check the hardware (such as cables, base radios, MLC 8000 Subsite Link Converters).
    5. If a full scale signal displays in the Audio Monitoring and Calibration window, adjust the Input From Radio/Console slider and click Start to resume audio monitoring. Repeat until the signal takes no more than 70-80% of the scale and press Calibrate.
  15. Using the wiring scheme and a multi-meter, verify all the pins from RJ45 to GTR 8000 are correct.