Trouble Shooting

Antenna | Intercom | Radio

Two-way radio antenna troubleshooting

It is critical that the antenna be in place and connected to the radio before proceeding. See drawing in installation instructions page. Test the antenna prior to connecting it. If you are using the antenna provided by Comp Comm, passing the following test will not guarantee that the antenna is OK, but failing it will guarantee that it is bad.

Using an ohmmeter or continuity tester and with the PL259 antenna connector disconnected from the radio test between the outer barrel of the connector, and the inner contact pin.This must show open. Next, test between the inner contact of the connector and the actual whip of the antenna. This must show continuity. Do not connect the antenna if either of these tests fail. The greatest likelihood of failure is in the wiring of the PL259 connector. Any “escaped” braid in the connector will cause a short between the barrel of the connector, and the center pin, and will render the antenna not only useless, but the short will represent a potential danger to the final transistor of the radio transmitter.

It is interesting to note that even with a bad or shorted antenna, the receiving (incoming) signal at the radio will be less compromised than the transmitted one.

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Intercom & helmets/headset troubleshooting

Start with the basics, and the 12 volt battery power to the unit is the most basic. Be sure that the vehicle battery is connected, and is fully charged. Often race vehicle batteries become discharged and can confuse testing of electronic systems. When you are sure that the DC power is OK apply power to the intercom unit. In the case of a Generation II model, switch it on by rotating the volume (right hand knob) clockwise. The LED should light; red on the Generation I and green on the Generation II. If the pilot light does not come on check the voltage with a voltmeter at the actual point that the power is connected tot he intercom leads. A fully charged battery will show 11.5-12 volts. If power is present, check for fuses or circuit breakers in the line. If the pilot light on a Generation II shows yellow, instead of green, it is in the transmit mode, and a keying switch is closed, or cable shorted to ground.

In order to isolate problem areas or components begin by disconnecting any accessory units; the two way radio, entertainment radio, keying switches and VCR/audio recording output. Check the vehicle harness for cuts, or breaks. Remember, this cable may not be spliced. In the case of a Generation II unit, check that the 25 pin connector mating the harness to the intercom is securely connected, and has no corrosion present at either end.

The Comp Comm intercoms are multi-channel amplifiers, and provide the user with a side tone. This enables you to hear yourself in your helmet/headset when you talk, and this provides a valuable trouble shooting tool. Begin by assembling all of your helmet/headsets, and plug them in one at a time. Speak into the mic, and see if you hear yourself in the earphones. If you do, then you have confirmed that unit is working, and so is that cable of the vehicle harness, and so is that path of the amplifier. Set that unit aside and test all of the other units in the same jack. Send any that fail back to us for repair. If none of them work, then repeat the entire process using a different helmet/headset jack. If they work on a different jack, repeat the process for all the jacks you have to determine which have failed.

The most common problem is a broken connection at a helmet/headset jack, and the second most common failure is as a result of a cut or break in a lead going to a jack. In the case of a Generation II unit a replacement cable may be ordered. With a Generation I unit the cable are an integral part of the unit, and the entire unit must be removed and sent to us for repair. Once you have identified at least one working helmet/headset, use it to test all jacks. Then you may plug other helmet/headsets into the system, but don't allow yourself to become confused. Remember, your prior testing has shown which headsets/helmets are working, and what jacks are working (if any).

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Two way radio Troubleshooting

By following the testing procedures outlined in the intercom troubleshooting section we have determined that the intercom and at least one helmet/headset are working. Do not proceed to this step unless this is correct.

The most frequent report of perceived failure of a two way radio integrated into the intercom system is that the unit will not transmit out. This is almost always caused by incorrect installation in the form of inadequate DC power being available to the radio when it goes into the transmit mode due to the radio not being connected directly to the battery or the wires connecting the radio to the power are too small a gauge for the distance run. This results in a shut down of the radio when the transmit button is pressed.

Begin by reconnecting the lead from the intercom to the two way radio. Remember that only radios specially modified by Comp Comm are compatible with your system. Radios not so modified will not work. After connecting the radio, connect at least one of the two push-to-talk switches. These are normally open, single pole, single contact, momentary contact switches. They apply chassis ground to put the radio into the transmit mode. Do not use any switch that is not momentary contact as damage to the transmitter may result.

With the radio connected, measure the voltage at the connector supplying the 12 volts to the radio, with the radio on. It should show approximately 12 volts. Now, pres the transmit button and observe the voltage reading. It must be more than 10.5 volts, if it is not, the radio will NOT GO INTO TRANSMIT MODE. On some models the LED display on the front of the radio will show "8s". This is a condition normally brought about by running too small a gauge of wire to the radio from the battery (all though it can be caused by a low battery too). It is important that the DC power leads (both positive and negative) are both run as directly to the battery as possible, using as large a gauge of wire as practical (the actual gauge required will vary with the distance run).

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