9-8. OPERATIONAL CHECK.
The operational check provides a step-by-step procedure for evaluating a PA mount. If the operational check is
passed, the PA mount can be returned to service. If it does not pass the test, the bad module or the
troubleshooting chart to be used will be identified. The troubleshooting procedures are in paragraph 9-9.
The operational check is divided into steps. Each step verifies a particular function. Follow the instruction in the
Action column. Check the response. If the response is correct, proceed with the next lettered step. When a
Step has been completed, proceed with the next Step. A No response in the Response column means that
any response is not of interest.
The switch settings for the test equipment are given in the EQUIPMENT PRESETS section of each test setup
figure. Set the test equipment switches to the indicated presets and then verify the settings. If a test response is
incorrect, check the equipment settings and the test adapter cabling before going to a troubleshooting chart or
replacing a bad module.
High voltage (200 V dc) is present at PA mount connector J4 . Use caution when connecting the
test setup and taking measurements to avoid personal injury.
Connect the test setups only when directed, and with the power supply set to OFF. The large
current capacity of the test power supply can cause personal injury. Verify the test setup before
turning the power supply ON.
Step 1. TURN-ON CHECK.
a. Remove connector caps from connectors
a. No response.
J1, J3, and J4.
b. Adjust test power supply for 27 V dc.
b. No response.
c. Connect test setup as shown in figure 9-2.
c. No response.
d. Turn-on test power supply.
d. Test power supply circuit breaker does not
Set 28 V: ON.
trip. If the circuit breaker trips, the chassis
e. Set PA mount CB1: ON.
e. DS1 does not light. If it does, relay K1 is
bad. CB1 does not trip. If it does, the
chassis is bad.
f. Connect TP4 to TP5 with jumper cable.
Listen for relay contacts to close.
Relay contacts close. If they do not,
the chassis is bad.
2. CB1 remains at ON. If it trips to OFF,
go to chart 1.
3. DS1 lights. If it does not, go to