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TM 11-6625-3145-14
Theory of Operation-318/338 Service
Figure 4-6. 318 Simplified diagram of the acquisition memory and ACQ address counter circuit.
Acquisition Memory. The 256-word X 32-bit high-speed memory consists of RAMs A04U116, A04U118, A04U120,
A04U122, A04U124, A04U126, A04U128, and A04U130. The ACQ memory location of each data bit to be stored is
controlled by the address counter. These memories operate in either write or read mode. In the write mode, the low level
of the WE pulse, applied to pin 8 of each RAM, stores the input data in the location defined by the ACQ Address Counter.
During the write operation, a low on the CS0, CS1 , CS2, and CS3 lines enables the RAMs. When the RAMs are in the
read mode, a high on their WE input prevents them from accepting new data. Data in the RAMs can be sequentially read
by incrementing the ACQ address counter after each read operation. The outputs of the RAMs are connected to the data
selector (A04U142 and A04U144 <9>).
ACQ Address Counter and Carry Latch. The ACQ address counter designates the memory location of each data bit to
be stored. The counter, consisting of A04U136 and A04U138, is a synchronous, 8-bit (divide by 256) binary counter which
is reset to zero by the RESET signal from the A03 ACQ Control board at the beginning of each acquisition.
The counter outputs Q0 through Q3 are connected to the address inputs of A04U116, A04U118, A04U120, U122,
A04U124, A04U126, A04U128, and A04U130.
Counter U138 provides a carry output to the carry latch (A04U139A). After one full memory cycle, the carry latch provides
a latched low-level signal on the output of A04U139A pin 2. It serves as the address counter CARRY signal.
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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 ...
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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 ...