TM 55-4920-431-13
INTRODUCTION
GENERAL
INFORMATION
Section I.
Part No. 161226-200 referred to herein as the tester figure 1-1, is used to troubleshoot
an Auxiliary Power Unit (APU) and Electronic Sequence Unit (ESU), either in the air-
craft or in a maintenance shop or test cell.
1-2. Capabilities. The tester allows the user to dynamically test the APU and ESU
independent of all aircraft controls and to isolate a fault to a malfunctioning com-
ponent or part. Refer to fault logic tree in the applicable maintenance manual.
1-3. The tester can be used to control the APU and monitor all functions, to test
the APU in a test cell after overhaul or repair.
1-4. The tester can be used in a maintenance shop for troubleshooting or repair
of the ESU.
Figure 1-1. Tester
