558
Chapter 11
Synthesizer Section
Unlocked YTO PLL
40.Change the
CENTER FREQ
to 678.8 MHz with the SPAN remaining
0 Hz. This will change the switch setting of U326A and invert the
voltages listed in
.
Check main coil
coarse and fine
DACs (steps
41-46)
41.The main coil coarse and fine DACs correct any initial pretune
errors in the YTO main coil. The DACs adjust the FM-coil current to
zero before any sweep begins. Refer to function block J of A14
frequency control schematic (sheet 2 of 5).
42.Set the spectrum analyzer to the settings listed below. This sets both
DACs to 128 (the DAC setting range is 0 to 255).
Center frequency .................................................. 300 MHz
Span .............................................................................. 0 Hz
Trigger ......................................................... SINGLE, EXT
(with no external trigger connected)
43.Press
SAVE
,
PWR ON STATE
and turn off the spectrum analyzer.
44.Place A14J23 jumper in the TEST position and turn on the spectrum
analyzer.
45.Verify the voltages listed in
46.Place A14J23 jumper in the NORMAL position.
Check main coil
tune DAC (steps
47-49)
47.Set the spectrum analyzer to the following settings:
Center frequency ........................................................ 300 MHz
Span .................................................................................... 0 Hz
48.Place A14J23 jumper in the TEST position.
Table 11-6
Voltages in FM Coil and Main Loop Drivers
Measurement Points
Voltages
A14U405 pin 6
+3.116 Vdc
A14U322 pin 2
approx. +1.5 Vdc
A14J17 pin 4
>+10 Vdc
Table 11-7
Main Coil Coarse and Fine DACs Voltages
Measurement Points
Voltages
A14J17 pin 2
−
5 Vdc
A14J17 pin 3
−
5 Vdc
A14J17 pin 5
+5 Vdc
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 223: ......
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 ...
Page 284: ......
Page 285: ......
Page 286: ......
Page 287: ...377 8 ADC Interface Section ...
Page 291: ...Chapter 8 381 ADC Interface Section Introduction Figure 8 2 A3 Test Connector Pin Locations ...
Page 321: ......
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 453: ......
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 ...
Page 504: ......
Page 505: ...671 14 Component Level Information Packets ...
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