Garmin GI 275 Installation Manual page 249

Gyro Alignment Procedure
1. Remove the KC 19X computer from the mounting rack.
2. Connect the test harness as shown in Figure 5-26 to allow access to the adjustment pots (one on the
front and three on the side) and the three signal test pins.
3. Power the GI 275 in Configuration mode.
4. Navigate to the Gyro Output Test page (Calibration/Test → Autopilot → Gyro Output Test).
5. Verify that the internal AHRS test values are 0° pitch and 0° roll and are valid (ie., Attitude Valid
button illuminated green).
6. Measure the voltage from test pin 2 (J19x1-22) to test pin 3 (J19x2-10) with a digital voltmeter.
7. Adjust the RN potentiometer to obtain a voltmeter reading of 0.0 VDC.
8. Measure the voltage from test pin 1 (TC101-A4) to test pin 3 (J19x2-10) with a digital voltmeter.
9. Adjust the PDN potentiometer to obtain a voltmeter reading of 0.0 VDC. This step is not
applicable to the KC 190/KAP 100.
10. Set the internal AHRS Output to 25° RT using the right ROLL arrow.
11. Use a digital voltmeter to measure the voltage (+) at test pin 2 (J19x1-22) with reference to test
pin 3 (J19x2-10).
12. Adjust the RDG potentiometer to obtain a voltmeter reading of -5 ± 0.1 VDC.
13. Set the internal AHRS Output to 25° LT using the left ROLL arrow.
14. Verify that the voltmeter reading is now +5 ± 0.1 VDC.
15. Set the internal AHRS Output to 0° RT using the right ROLL arrow.
16. Set the internal AHRS Output to 10° DN using the down PITCH arrow.
17. Use a digital voltmeter to measure the voltage (+) at test pin 1 (TC101-A4) with reference to test
pin 3 (J19x2-10).
18. Adjust the PDG potentiometer to obtain a voltmeter reading of +2 ± 0.1 VDC. This step is not
applicable to the KC 190/KAP 100.
19. Set the internal AHRS Output to 10° UP using the up PITCH arrow.
20. Verify that the voltmeter reading is now -2 ± 0.1 VDC. This step is not applicable to the KC 190/
KAP 100.
21. When the testing is complete, remove the test harness.
Re-insert and secure the KC 19X computer into the rack.
190-02246-10
Rev. 11
GI 275 Part 23 AML STC Installation Manual
Page 5-71