System information

Maintenance & Troubleshooting DAC-2202 Antenna Control Unit
7-2
7.3. 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.
7.3.1. STEP-BY-STEP
1. Verify that the GYRO TYPE parameter is set correctly.
2. 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 4 connections to A, B, C and
COMMON.
3. Check the connections to the Terminal Mounting Strip and to the ACU.
4. 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.
5. 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.
7.3.2. 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.
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.
1. 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.
2. 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.