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TM 11-6625-3145-14
Maintenance: Troubleshooting-318/338 Service
Step 2. A word is read from a diagnostic cell and checked with the expected word 15.
If it is not equal to word 15, an error message is displayed and the MPU is halted.
Step 3. If the first test is successful, the word 2A is written into that cell. The word is then read back out of the cell and its
value is compared with 2A. If it is not equal to 2A, an error message is displayed and the MPU is halted.
Step 4. Steps 2 and 3 are repeated for all RAM addresses.
Troubleshooting - This test is the same as that automatically run when the power is first turned on, but here the looping
test feature is available. The LOOP field can have any of the following 4 options; OFF, I/O, ERROR, and TEST. When
the field is set to I/O, the looping feature allows only I/O instructions to be run repeatedly. The I/O address will appear on
the screen. When the field is set to ERROR, the looping feature allows the tests in which an error is detected to be run
repeatedly. When the field is set to TEST, the looping feature allows one test, or sequence of tests, to be run
continuously. When the field is set to OFF, the looping feature is not available and one test, or sequence of tests, runs
once.
When the field is set to I/O or ERROR, the prompt message START TO ADVANCE appears at the bottom of the the
screen. If START is pressed during LOOP tests, the current loop of the test stops and the next loop of test is started, You
can change fields during tests. Use this feature to catch intermittent faults and for circuit tracing with an oscilloscope.
In the I/O Looping test, only one or more OUT instructions (subroutines) including one of the following addresses will be
run. Unless STOP is pressed, this test will loop continuously without displaying the result of the verification. Use an
oscilloscope to observe the word recognizers.
Table 7-5
318 WORD RECOGNIZER TEST PORT ADDRESSES (Hex)
Address
Content of Looping Test
03
increment WR-address counter for WRO test.
5B
write WRO data55 into data latch.
5B
write WRO dataAA into data latch.
03
increment WR-address counter for WRI test.
5B
write WR1 data55 into data latch.
5B
write WR1 dataAA into data latch.
The ERROR looping feature is available only if errors are detected. If no errors are detected the test will perform as if the
LOOP test were set to OFF. If some errors are detected, the ERROR looping feature is available for the read cycle of the
test. and the result of this verification will appear on the screen. Refer to
of this manual for a description of
error codes.
Description: Refer to Figure 7-7. On the A01 INPUT-A board, data from channels 0 through 7 (Pod- A) is latched by
M218s U100 through U114 <1> (logic analyzer input, M218) and supplied to the word recognizer (WR) U120 (256 word X
7-14
Summary of Contents for 318
Page 119: ...318 VERIFICATION AND ADJUSTMENT PROCEDURES ...
Page 182: ...338 VERIFICATION AND ADJUSTMENT PROCEDURES ...
Page 253: ...318 ___________________ TROUBLESHOOTING TREES ...
Page 344: ...338 TROUBLESHOOTING TREES ...
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Page 518: ...TM 11 6625 3145 14 318 338 4434 924 338 Block Diagram ...
Page 519: ...TM 11 6625 3145 14 318 338 4434 925 318 Acquisition Module Wiring Diagram ...
Page 520: ...TM 11 6625 3145 14 318 338 4434 926 318 338 Mainframe Wiring Diagram ...
Page 521: ...TM 11 6625 3145 14 318 338 4434 926 338 Acquisition Module Wiring Diagram ...
Page 522: ...TM 11 6625 3145 14 318 338 4434 928 Figure 9 1 318 A01 Input A Board Component Locations ...
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Page 544: ...TM 11 6625 3145 14 Figure 9 9 318 338 A11 Inverter Board component Locations ...
Page 546: ...TM 11 6625 3145 14 Figure 9 10 318 338 A12 Regulator Board Component Locations ...
Page 551: ...TM 11 6625 3145 14 Figure 9 12 338 A01 Input A Board Component Locations ...
Page 553: ...TM 11 6625 3145 14 318 338 SERVICE ...
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