TM 11-6625-3145-14
Maintenance: Troubleshooting-318/338 Service
During the read phase, the MPU receives data from U152 (octal buffer/line driver with 3-state output, 74LS 244) by issuing
READ ACQ DATA at I/O address 59
hex
. The READ ACQ DATA signal switches the inputs of U142 and U144 (quad 2-
input multiplexer, 10158) on the A04 board to the output of the ACQ Memories.
Outputs of the ACQ Memories are wired together with the outputs of U146 (quad 2-input multiplexer/latch, 10173) on the
A03 board, or with Threshold TEST from U244C (QUAD 2-INPUT NOR GATE, 10102) on the A02 board via the A08
Mother board. These signals must be kept low in order to read the correct data from the ACQ Memories. To write 0’s into
U146 (10173) on the A03 board, the MPU loads 00 into the SQRAM U144 (256 word X 4 bit RAM, HM10422) on the A03
board, then changes the inputs of U146 (10173) to the SQRAM output and issues READ SQRAM . The output of U244C
(10102) on the A02 board can be disabled by writing 1XXXX
binary
serially into U224 (hex D master-slave flip-flop, 10176)
on the A02 board at I/O address O1
hex
.
The data read is checked by the MPU and an error message is displayed if the data is incorrect.
The MPU also checks the interrupt from the carry flip-flop U139A on the A04 board. The carry flip- flop is set when U136
and U138 (F10016) on the A04 board issue a carry bit at the same time.
10.
SEQUENCE RAM TEST
Program: SQRAM
Function:
Power on - The SQRAM is checked with the checkerboard marching pattern from 00 through FF.
Step 1. The word 55 is written into all RAM addresses.
Step 2. A word is read from a diagnostic cell and compared with the expected word 55. If the selected word is not equal
to 55, an error message is displayed and the MPU is halted.
Step 3. The word AA is written into that diagnostic cell. Then a word in same cell is read back and is compared with AA.
If it is not equal to AA, 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 run automatically when the power is first turned on, but here the looping
feature is available. The looping feature has 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, will run once.
When I/O looping is selected, only those looping instructions including one of the addresses listed in Table 7-7 will run.
Unless the STOP key is pressed, the program will continue looping without displaying the result of the verification. In this
case, the user should observe the ACQ. circuit board with an oscilloscope.
7-20
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 ...
Page 517: ...TM 11 6625 3145 14 318 338 4434 923 318 Block Diagram ...
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 ...
Page 526: ...TM 11 6625 3145 14 ...
Page 528: ...TM 11 6625 3145 14 Figure 9 3 318 338 A03 ACQ Control Board Component Locations ...
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Page 542: ...TM 11 6625 3145 14 Figure 9 8 318 338 A10 CRT Board Component Locations ...
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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Page 555: ...PIN 058584 ...