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Chapter 7
General Troubleshooting
Block Diagram Description
Triggering
The spectrum analyzer has five trigger modes: free run, single,
external, video, and line. The free run and single trigger signal comes
from the 1 MHz ADC clock. The line trigger signal comes from the A6
power supply. Video triggering originates from the A3 video filter buffer
circuit. External triggering requires either a high or low TTL logic level
as determined by the setting of the trigger polarity function. The
external trigger signal is received from a rear panel BNC connector. A
DAC in the trigger circuit sets the video trigger level. The trigger
circuit is responsible for setting HSCAN high.
Controller Section
The controller section includes the A2 controller assembly and A19
GPIB assembly. The battery on the rear panel provides battery backup
for state and trace storage.
In 8564EC and 8565EC instruments the A2 contains the CPU, RAM,
ROM, the display ASM, Fast ADC circuitry, GPIB interface, control,
frequency counter, display RAM, option module interface, and EEROM.
The A19 GPIB is a mechanical interface between the standard GPIB
connector and the ribbon cable connector on the A2 controller assembly.
All four RAM ICs are battery-backed. The battery-backed RAM stores
trace information (two display memory RAMs) and spectrum analyzer
state information (two program RAMs). A total of eight traces and ten
states may be stored. Typical battery life is five years with the lithium
battery. Trace and state information may be retained for up to
30 minutes with a dead battery and power turned off. This is due to the
very low data retention current of the RAM.
EEROM
The EEROM stores important amplitude-related correction data. This
includes data for LO distribution amplifier DACs, preselector slope and
offset DACs, RF gain DACs (flatness correction), and preselector peak
DAC. The spectrum analyzer serial number, model number, and
installed options are also stored in EEROM.
Firmware The spectrum analyzer firmware reads the model number
and installed options from the EEROM to determine how to respond to
certain keystrokes.
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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