Theory of Operation
3-8
371B Service Manual
3. X 10-bit DAC & Y 10-bit latch
4. X & Y low-pass filter
5. Font latch
6. Character ROM & shift resister
7. X & Y readout position latch
8. Readout attribute latch
9. 8-bit adder
10. X readout step generator
11. X readout DAC and Y readout DAC
These circuits convert the digitized waveform data, readout data and cursor data
from the display RAM into an analog signal and generate the Z-axis signal.
The display offset circuitry is located on the A5 Display Control board. The
display offset circuitry consists of the control logic circuit, offset D/A converter
circuit, polarity select circuit, source select circuit, zero & invert select circuit,
and X and Y gain select circuits. These circuits select the horizontal and vertical
source inputs for the CRT display and provide invert, collector supply polarity,
and peak power watts.
The display select circuitry is located on the A5 Display Control board. This
circuitry consists of the signal select logic circuit, unblank & Z select circuit, and
the horizontal & vertical preamp circuit. This block of circuitry selects and
amplifies the source inputs that are displayed on the CRT. Selection of the source
inputs are performed by the signal select logic circuit. The Z signal for the source
inputs is controlled by the unblank & Z select circuit.
The collector supply amplifier consists of a collector power supply circuit and
collector supply amplifier circuit.
The collector supply amplifier amplifies signals from the sine-square wave
generator (located on the A3 A/D board) to provide driving voltage for the
collector supply transformer.
The step generator voltage amplifier consists of the 1-2-5 ranging circuit, the +55
and –55 V power supply circuit and the voltage amplifier circuit. This circuit
transforms the output of the step generator on the A3 A/D board into voltage
steps of various amplitudes to be applied to the device under test. The STEP/
Display Offset Circuit
Display Select
Collector Supply Amplifier
Step Generator Voltage
Amplifier
Summary of Contents for 371B
Page 4: ......
Page 14: ...Service Safety Summary 371B Service Manual...
Page 18: ...Preface 371B Service Manual...
Page 21: ...Specifications...
Page 22: ......
Page 24: ...Product Overview 371B Service Manual...
Page 38: ...Specifications 371B Service Manual...
Page 39: ...General Information...
Page 40: ......
Page 58: ...General Information 371B Service Manual...
Page 59: ...Theory of Operation...
Page 60: ......
Page 62: ...Theory of Operation 3 2 371B Service Manual Figure 3 1 371B Block Diagram...
Page 71: ...Maintenance...
Page 72: ......
Page 101: ...Performance Verification...
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Page 220: ...Performance Verification 371B Service Manual...
Page 221: ...Options...
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Page 226: ...Options and Accessories 371B Service Manual...
Page 227: ...Electrical Parts List...
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Page 235: ...Diagrams...
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Page 237: ...8 1 371B Service Manual Circuit Board Interconnections 2 2...
Page 238: ...371B Service Manual...
Page 239: ...8 3 371B Service Manual Circuit Board Interconnections 2 2...
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Page 241: ...8 5 371B Service Manual Test Point Adjustment Locations 1...
Page 242: ...8 6 371B Service Manual Test Point Adjustment Locations 2...
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Page 245: ...8 9 371B Service Manual Troubleshooting Tree...
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Page 247: ...8 11 371B Service Manual Troubleshooting Tree Cont...
Page 248: ...371B Service Manual...
Page 249: ...Mechanical Parts List...
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Page 259: ...9 9 371B Service Manual Figure 9 1 Cabinet Rear 97 96 68...
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Page 261: ...9 11 371B Service Manual Figure 9 2 Display Front 73...
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Page 267: ...9 17 371B Service Manual Figure 9 3 Chassis Ciircuit Board...
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Page 269: ...9 19 371B Service Manual Figure 9 4 Power Supply...
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Page 276: ...Mechanical Parts List 371B Service Manual...
Page 277: ...9 27 371B Service Manual Figure 9 5 Test Fixture 78 78 REV MAR 96 75 72...
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Page 279: ...9 29 371B Service Manual Figure 9 6 Front Porch...
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