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Installation Troubleshooting
17.2. Troubleshooting Ships Gyro Compass problems
Ships Heading display does not follow ships movement and/or you are getting frequent or constant ERROR CODE
0001. Determine the type of gyro compass that is used on the ship, assure that the GYRO TYPE parameter is set
correctly (refer to the setup section of this manual) and then proceed to the step that lists the troubleshooting for the
correct type of Gyro Compass Signal.
17.2.1. STEP-BY-STEP
1.
2.
3.
4.
5.
17.2.2. 1:1 SYNCHRO
Observe the ship's heading display on the ACU. Compare its movement with that of the ship. If it does not
move at all go to step 1. If it moves but in the wrong direction (even if it does not display the correct
heading) go to step 2. If it moves in the correct direction but does not display the correct heading go to step
3. The gyro compass connects to the Terminal Mounting Strip on TB3 R1, R2, S1, S2 and S3.
1.
2.
3.
Verify that the GYRO TYPE parameter is set correctly.
Observe the ERROR LED on the FRONT panel. If it is illuminated, this indicates that an error was
detected in the Step-By-Step input. Press RESET on the front panel. If the ERROR LED illuminates
again, the problem is in the four connections to A, B, C and COMMON.
Check the connections to the TMS and to the ACU.
Measure the voltage between COMMON and A, B, and C. Each reading should either be near zero or
35 to 70 VDC. If all three are zero, check the repeater fuses. If some read negative and some read
positive or if one reads an intermediate values the COMMON terminal is not properly connected.
If the Ship - Heading display is different from the actual Gyro heading, access the Heading entry
menu and key in the correct heading value (refer to the operation Ship menu section). Note the
reading. After the ship has turned more than one degree, compare the new gyro heading with the
reading on the display, if it has moved in the opposite direction then reverse connections A and B.
Reset the ACU, put in the correct ship's heading again and verify that the display reading now
follows the Gyro heading.
CAUTION - Electrical Shock Potentials exist on the Gyro
Compass output lines. Assure that the Gyro Compass output is
turned OFF when handling and connecting wiring to the
Terminal Mounting Strip.
The Ships Heading display does not change when the ship changes direction. Using a
multimeter read between R1 and R2. It should read 115 VAC. If it does not then a fuse is blown at
the gyro repeater or there is an open between the repeater and the ACU. Read between S1 and S2,
S2 and S3 and finally S3 and S1. They should all read between 0 and 90 VAC. The voltage level will
change as the ship turns. If one reading is very close to 0 volts wait until the ship has made a major
change in heading and then check voltage again. If the reading is still very low there is a problem in
the line between the gyro repeater and the ACU or a problem in the gyro repeater itself.
The display changes in the direction opposite of the movement of the ship. Switch the
secondary leads S1 and S2. Caution: there is 90 VAC between them! Verify that when the ship
changes direction the display shows change in the same direction. If the direction is correct but the
heading is incorrect go to step C.
The ship's heading display does not indicate the correct heading. If the display is off by
60, 180 or 300 degrees, this indicates that R1 and R2 are reversed. Reverse R1 and R2 and recheck
the heading display. If the display is off by 120 or 240 degrees, this indicates that S1, S2 and S3 are
in the right order but off by one place. Note their positions and carefully move the connections one
position over (S1 to S2, S2 to S3, and S3 to S1). This action will offset the display by 120 degrees.
Check if the display now reads correctly. If not move all three leads one more time in the same
direction as last time. Verify that the ship's heading is correct.
9711-92 Ku-Band TXRX
17-2
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Table of Contents
Troubleshooting
