System Maintenance Manual

Page 7-18 G1000/GFC700 System Maintenance Manual – C90A/C90GT/C90GTi King Air

Revision F 190-00682-01

7.4.2.6 Prop Tach (N2) Functional Test

Required test equipment:

Test Equipment Make/Requirement Model/Part Nbr

Signal Generator 0-10Vdc / 0 – 1k Hz As appropriate

1. Using a signal generator, inject a 2.5 Vrms signal into the No. 1 TACH-GEN Adapter via left

engine firewall connectors-pins J102-W and J102-X.

2. Simulate the following frequencies, and verify the indication and status:

Test Point (Hz) Indication (rpm) Status Configurations

35.1 +/- .4 1100

bottom of green band

Green digital

9-10, 13, 16-18

47.9 +/- .4 1500

51.1 +/- .4 1600

1-8, 11-12, 14-15, 20

57.5 +/- .4 1800

red digital*

NOTE: red radial 1750

11-13

62.3 +/- .4 1950

red digital*

NOTE: red radial 1900

1-3, 14-19

71.8 +/- .4 2250

red digital*

NOTE: red radial 2200

4-10, 20

(*) steady after 5 seconds

3. Repeat steps 1 and 2 using the No. 2 TACH-GEN Adapter via right engine firewall connectors-pins

J103-W and J103-X.

4. If no other tests will be completed in this section, do the following:

a. Disconnect test equipment.

b. Ensure firewall connectors are reconnected.

c. Verify all engine parameters are displayed valid on the MFD with no Red X’s.