TERION UM20-100111B, Руководство по установке, Страница: 56 / 78

When troubleshooting a system it is very important that you approach it methodically. If
some aspect of the Mobile Messaging System is not responding as anticipated, change that
part or component and then retest the system. Do not make more than one change at a time,
or it may mask other problems. Following the type of troubleshooting below will minimize
guesswork, effort and rework.
13.1 12 VDC Power Connection
If the system fails to boot, it is usually caused by the power hook-up, or a short circuit.
Below is a list of questions that should be asked and verified first.
1. Is the power cable connected to the ITU? If not, connect it.
2. Were all connections made to the fuse panel (power source)? If not, make the
connections as described in this manual (see Section 7, Power Connections). Verify
that you have connected the red wire to the non-switched (hot), and the yellow wire to
the switched (key-controlled) points in the fuse panel. Verify that the black wire is
connected to a good ground with less than 1.0 ohm resistance to the negative battery
cable.
3. Did you place the proper size fuse into the fuse holder? If not, install the proper size
fuse. Are fuses blown?
4. Using a voltmeter, check that there is approximately 12-18 VDC supplied to the
connector. Do this using the supplied ITU Power Test Adapter cable. If not, look
for a cut in the power cable. If no cut is found, verify that the truck has 12-18 VDC.
If not, contact the operator.
13.2 Calibration Quality Index (CQI)
A CQI of 96 or better must be reached before an installation can be deemed successful.
When a calibration is performed, and it is completed very quickly (in seconds), or in a very
long time (more than 8 minutes), it usually indicates a problem, regardless of the CQI value
eventually obtained. You should check the installation, reset the ITU by disconnecting the
power cable for 10 seconds, and redo the Calibration as outlined in Section 10, Calibration.
Below is a list of questions that should be asked and verified first.
1. Is the coaxial cable properly connected to the FM/DHF antenna connector?
2. Is the coax cable crimped or pinched in any way? If the cable has been damaged,
replace it. Do not attempt to modify or repair any coaxial cable.
3. Is the antenna tightened onto the antenna connector? Is the lock washer installed and
compressed? If not, tighten as instructed in Section 4, FM/DHF Antenna Installation.
4. Is the antenna connector installed correctly?
5. Is the FM/DHF antenna coaxial cable tightly connected to the ITU? It should be
firmly hand-tightened.
If all of the above items are found to be okay, there could be an electrical short in the system.
The following steps will check for these types of problems.
13-2
Mobile Messaging System Installation Manual June 15, 2001
UM20-100111B Terion, Inc.