Garmin G1000 Nxi System Maintenance Manual page 302

Prop Tach N2 Functional Check
Required test equipment:
If the left engine gauge needs to be tested, perform the following:
1. Ensure that Prop Sync switch indicator located on the instrument panel is not depressed.
2. Disconnect the J102 firewall connector.
3. Apply external power to aircraft and start the G1000 system in normal mode.
4. Inject a 2.5Vrms sine wave signal into the No. 1 TACH-GEN Adapter by connecting the
Signal Generator to the left engine firewall connector-pins J102-W (HI) and J102-X (LO).
5. Allow five seconds for the input signal to stabilize after changes before verifying the
indications.
6. If the test input shows a correct gauge reading within the Indication tolerance in Table
7-4, troubleshoot the tach sensor per the Beechcraft King Air 300 Series Maintenance
Manual.
7. If the test input shows an incorrect gauge reading outside the Indication tolerance in
Table 7-4 perform the following:
a. Check gauge circuit wiring for faults.
b. Replace the Signal Conditioner.
c. Replace GEA 1.
8. If no other EIS gauge tests are needed, reconnect and safety the J102 connector and
reinstall the engine cowling(s).
If the right engine gauge needs to be tested, perform the following:
1. Ensure that Prop Sync switch indicator located on the instrument panel is not depressed.
2. Disconnect the J103 firewall connector.
3. Apply external power to aircraft and start the G1000 system in normal mode.
4. Inject a 2.5Vrms sine wave signal into the No. 2 TACH-GEN Adapter by connecting the
Signal Generator to the left engine firewall connector-pins J103-W (HI) and J103-X (LO).
5. Allow five seconds for the input signal to stabilize after changes before verifying the
indications.
6. If the test input shows a correct gauge reading within the Indication tolerance in Table
7-4, troubleshoot the tach sensor per the Beechcraft King Air 300 Series Maintenance
Manual.
7. If the test input shows an incorrect gauge reading outside the Indication tolerance in
Table 7-4 perform the following:
a. Check gauge circuit wiring for faults.
b. Replace the Signal Conditioner.
c. Replace GEA 2.
G1000 NXi System Maintenance Manual
King Air 300 Series
190-00716-N1
Test Equipment Make/Requirement
Signal Generator 0-10Vdc / 0 – 1k Hz
Page 289
Revision 1