Chapter 11
527
Synthesizer Section
Troubleshooting Test Setup
Troubleshooting Test Setup
Some synthesizer section problems require placing the YTO PLL in an
unlocked condition. This is done by moving jumper A14J23 to the TEST
position. This grounds the YTO ERROR signal and disables the CPU
from detecting an unlocked YTO. The FM coil driver output is set to its
mid-range level causing the YTO to be controlled only by the main coil
tune DAC.
Synthesizer section troubleshooting is best done with the spectrum
analyzer SPAN set to 0 Hz (even though it is still possible to sweep the
Main and FM coils of the YTO).
With the YTO in its unlocked conditions and the SPAN set to 0 Hz, the
nominal YTO frequency is not necessarily the value listed as LO FREQ
in the Frequency Diagnose menu. The YTO has an initial pretune
accuracy of
±
20 MHz. To display the nominal YTO frequency, press
CAL
,
MORE 1 OF 2
,
FREQ, DIAGNOSE
,
LO FREQ
.
The fractional N oscillator frequency is the same as the desired sampler
IF. To display the fractional N oscillator frequency press
CAL
,
MORE 1
OF 2
,
FREQ DIAGNOSE
,
FRAC N FREQ
. If the sampler IF is negative
(YTO frequency is lower than the desired sampling oscillator
harmonic), the fractional N frequency will be displayed as a negative
number.
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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