Chapter 13
665
Display/Power Supply Section
A6 Power Supply Assembly
DC-DC Converter Control
See function block I of A6 power supply schematic diagram in the
component-level information binder.
The DC-DC converter control circuitry divides the 80 kHz squarewave
from U202A and generates two complementary 40 kHz squarewaves to
drive the FETs in the DC-DC converter. Also, U202D and its associated
circuitry monitor the voltage across sense resistor R116 in the DC-DC
converter. When the current through the FETs in the DC-DC converter
exceeds 1.8 A, the voltage across R116 will cause the output of U202D
to go high. This sets a latch in U204 which turns off U203.
Power Up
See function block M of the A6 power supply schematic diagram in the
component-level information binder.
The power up circuitry generates the PWR UP signal, which tells the
microprocessor that the supplies are up and stable. PWR UP will go
high when the +5 Vdc supply e4.99 Vdc. PWR UP will go low
when this voltage is less than +4.895 Vdc. Once PWR UP is set low, it
will stay low for at least 50 ms before going high, even if the +5 Vdc
supply e4.99 Vdc before 50 ms have elapsed.
Summary of Contents for 8564EC
Page 17: ...25 1 General Information ...
Page 37: ...47 2 Adjustment Diagnostic Software ...
Page 77: ...89 3 Manual Adjustment Procedures ...
Page 129: ...161 3a Manual Adjustment Procedures 3335A Source not Available ...
Page 142: ...175 4 Assembly Replacement ...
Page 194: ...Chapter 4 257 Assembly Replacement Procedure 13 A21 OCXO Figure 4 34 A21 OCXO Mounting Screws ...
Page 196: ...259 5 Replaceable Parts ...
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Page 224: ...303 6 Major Assembly and Cable Locations ...
Page 234: ...315 7 General Troubleshooting ...
Page 238: ...Chapter 7 319 General Troubleshooting Introduction Figure 7 2 Ribbon Cable Connections 1 of 3 ...
Page 239: ...320 Chapter7 General Troubleshooting Introduction Figure 7 3 Ribbon Cable Connections 2 of 3 ...
Page 242: ...Chapter 7 323 General Troubleshooting Introduction Figure 7 5 Service Cal Data Menu ...
Page 271: ...352 Chapter7 General Troubleshooting Block Diagram Description Figure 7 6 Functional Sections ...
Page 283: ...364 Chapter7 General Troubleshooting Block Diagram Description ...
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Page 287: ...377 8 ADC Interface Section ...
Page 291: ...Chapter 8 381 ADC Interface Section Introduction Figure 8 2 A3 Test Connector Pin Locations ...
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Page 322: ...427 9 IF Section ...
Page 356: ...Chapter 9 461 IF Section A5 IF Assembly Figure 9 13 Detailed IF Adjust Signature 5 ...
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Page 379: ...487 10 Controller Section ...
Page 394: ...521 11 Synthesizer Section ...
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Page 454: ...593 12 RF Section ...
Page 489: ...628 Chapter12 RF Section A15 RF Assembly Figure 12 10 10 MHz TTL Reference at U304 Pin 13 ...
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Page 492: ...633 13 Display Power Supply Section ...
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Page 505: ...671 14 Component Level Information Packets ...
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