TM 11-6625-3145-14
Maintenance: Troubleshooting-318/338 Service
5.
SYSTEM RAM TEST
Program:
Function:
Power on - System RAMs are checked with the chekcerboard marching pattern from addresses F000 through F7FF and
from F800 through FFFF.
Step 1. The word 55 is written into all RAM addresses.
Step 2. A word is read from a selected diagnostic cell and checked against the expected word 55.
If it is not equal to the word 55, an error message is displayed and the MPU is halted.
Step 3. If the first test is successfully completed, the word AA is written into that cell. Then the word in the same cell is
read back and 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 - None.
Description: RAMs U400 (F000-F7FF) and U401 (F800-FFFF) on the A06 MPU/Display board used by the MPU are
called System RAMs. The MPU data bus (D0-D7) and the partial MPU Address Bus (A0-A10) are directly connected to
these RAMs.
The chip-select signals, RAM1CS and RAM2CS are generated by U005 (dual 2-line to 4-line decoder/multiplexer,
74LS139) on the A05 ROM/Threshold board. These signals are sent to the System RAMs through the A08 Mother board.
The MPU checks these System RAMs with the checkerboard marching pattern. The read and write sequences have
already been mentioned in the preceeding
Power on
paragraph. If the data read is incorrect, the MPU will issue an error
message.
6.
ROM TEST
Program:
Function:
Power on - ROM1 through ROM6 are checked by individually calculating their checksums.
Troubleshooting - None.
Description: Refer to Figures 7-36 and 7-37. All the ROMs (ROM1 through ROM7) are located on the A05
ROM/Threshold board.
7-100
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 ...