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MAINTENANCE MANUAL

# DENOTES L, R, OR C COMPUTER
Ground Test - LRU - 04 MCP (Steps 1-5)
Figure 17 (Sheet 2)

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 GUN 001-050, 052-999 ú 22-41-00
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757 MAINTENANCE MANUAL
The MCP test checks the function of all lightswitches,
 controls, and displays on the AFCS mode control panel using a
 preprogrammed test routine with operator interaction. The
 tests are divided into three sections: testing the bottom half
 of the switch/lights, testing unlighted switches, and testing
 displays. A TEST COMPLETE message is displayed after all test
 steps are completed.
 1) The MCP lighted switches are tested by the MCDP sending a test command to the FCC's on ARINC 429 data buses. The FCC's send necessary data (on ARINC 429 data buses) to the MCP's lightswitches. This turns on all switch/lights. The operator presses each lighted switch; this is sensed by each FCC, and each must send the MCP an off command to turn the light off. a) GUN 051; the BARO switch/light is tested separately.
 2)  The testing of the unlighted switches is accomplished by the operator responding to instructions displayed by the MCDP. The test routine monitors AIM word 356 supplied from the FCC and detects the switch or control action. The test is automatically advanced to the next step after each correct test result. The test stops if the test result is incorrect. Pressing the YES/ADV switch continues the test after the test routine stops.
 3)  The MCP displays are tested by the operator responding to MCDP display messages and verifying that the display is in accordance with the MCDP message. Failure of the display to respond in accordance with the MCDP message indicates that the display is faulty. No fault messages are displayed on the MCDP. The operator must press the YES/ADV switch after each test, whether the result is correct or not, in order to continue the test.
MCP Test Steps Description
 1)  Step 1 - The MCDP CPU test select routine monitors the GRD TEST SEL UP (or NO/SKIP) and DOWN switches for a command to select another test until the required test arm message 04 MCP TEST? is displayed. The operator presses the YES/ADV switch to engage the 04 MCP TEST.
 2)  Step 2 - The MCDP displays 04 IN PROGRESS while checking its memory to see if any faulty FCCs and TMC were detected during the ground test entry function. Each fail message, 04 FCC (L, R, or C) FAIL, is displayed in sequence by pressing YES/ADV for the next fault. If there is no faulty TMC or FCC, the test automatically advances and checks for interface fault data stored in memory during the ground test entry functions. The 04 IN PROGRESS message is displayed while the CPU is checking for interface fault data.
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MAINTENANCE MANUAL

Step 3 - An interface fault message is displayed for each faulty FCC-to-MCP and TMC-to-FCC interface. Subsequent interface faults are displayed sequentially by pressing the YES/ADV switch. The MCDP can display up to six of the following FCC interface fault messages: a) The MCP BUS IN message indicates that the ARINC 429
 data bus from the MCP to the FCC is faulty.
 b)  The MCP A/P ENG DISC message indicates that the 28 vdc servo power engage interface from the FCC to the MCDP is faulty.
 c)  The A/P DISC SW message indicates that the control wheel A/P disconnect switch or interface is faulty.
 d)  The MCP A/P ARM IN message indicates that the +28 vdc servo power arm interface from the FCC to the MCP is faulty.
 e) The FCC TO MCP BUS IN message indicates that the ARINC 429 data bus from the FCC to the MCP is faulty. f) The TMC BUS IN message indicates that the ARINC 429
 data bus from the TMC to the FCC is faulty.Step 4 - If there are no interface faults, the test routine automatically advances to the MCP test and displays 04 MCP MAN TEST?. Pressing the YES/ADV switch enables the 04 MCP manual test.GUN 051; step 5 - Displays action message 04 PUSH BARO-VFY L/R LIGHTS-ADV for the operator to push the BARO switch and verify the alternate L and R light indication on the BARO switch.GUN 001-050, 052-999; Step 5 - The 04 manual test starts by testing all lighted switches. The MCDP commands the FCCs to do the MCP lighted switch test. The FCC turns on all lightswitches that are controlled by the FCCs. The MCDP then displays action message 04 PUSH OFF MCP LIGHTS and the operator pushes each MCP lightswitch. If the lightswitch pushed is functioning, the FCC senses that the switch has been pressed and sends a signal back to the MCP to turn that lightswitch off. If pressing the lightswitch does not cause the light to turn off, it is an indication that the lightswitch circuit is faulty. No fault message is displayed. The test advances to the next step when the FCC senses that all switches have been tested, or the YES/ADV switch is pressed.
　
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