574
Chapter 10
Synthesizer Section
A21 OCXO
A21 OCXO
The spectrum analyzer uses an oven-controlled crystal oscillator
(OCXO). It is deleted in Option 103 and replaced by a
temperature-compensated crystal oscillator (TCXO), located on the A15
RF assembly. Connectors J305 and J306 on the A15 RF assembly are
located where the TCXO would be installed in an Option 103. The oven
in the OCXO is powered only when the spectrum analyzer is powered
on; there is no standby mode of operation. The OCXO oscillator
operates only when the internal frequency reference is selected. Control
line HEXT (High = EXTernal frequency reference) is inverted by
A15U303B to generate LEXT. (Refer to the A15 RF assembly schematic
diagram, block M, sheet 2 of 4.) LEXT is sent to the OCXO via A15J306
pin 4. When LEXT is low, the oscillator in the OCXO will be turned off.
Replacement OCXOs are factory adjusted after a complete warmup and
after the specified aging rate has been achieved. Thus, readjustment
should typically not be necessary after OCXO replacement, and is
generally not recommended.
If adjustment is necessary, the spectrum analyzer must be on
continuously for a minimum of 24 hours immediately prior to oscillator
adjustment to allow both the temperature and frequency of the
oscillator to stabilize. Failure to allow sufficient stabilization time could
result in oscillator misadjustment.
Check operation of the A21 OCXO as follows:
1. Disconnect W49 (Coax 82) from A15J305. Connect the output of W49
to the input of another spectrum analyzer.
2. Check that the fundamental frequency is 10 MHz and that the
power level is 0 dBm
±
3 dB. Also check that the harmonics are at
least
−
25 dBc. Excessive harmonics can generate spurious responses
on the fractional N oscillator on the A14 frequency control assembly.
3. If the OCXO has no output, check A15J306 pin 1 for +15 Vdc. Check
A15J306 pin 4 for a TTL-high level.
4. If A15J306 pin 4 is at a TTL-low level, press
AUX CTRL
and
REAR
PANEL
. Press
10 MHz EXT INT
until INT is underlined. A15J306 pin 4
should read a TTL-high level. Press
10 MHz EXT INT
until EXT is
underlined. A15J306 pin 4 should read a TTL-low level.
Summary of Contents for 8560E
Page 17: ...16 Contents ...
Page 24: ...23 1 General Information ...
Page 49: ...48 Chapter1 General Information Sales and Service Offices ...
Page 50: ...49 2 Adjustment Procedures ...
Page 132: ...131 2a Adjustment Procedures HP 3335A Source not Available ...
Page 146: ...145 3 Assembly Replacement ...
Page 224: ...223 4 Replaceable Parts ...
Page 251: ...250 Chapter4 Replaceable Parts Firmware Dependent Part Numbers ...
Page 253: ...252 Chapter4 Replaceable Parts Firmware Dependent Part Numbers ...
Page 255: ...254 Chapter4 Replaceable Parts Firmware Dependent Part Numbers ...
Page 257: ...256 Chapter4 Replaceable Parts Firmware Dependent Part Numbers ...
Page 259: ...258 Chapter4 Replaceable Parts Firmware Dependent Part Numbers ...
Page 261: ...260 Chapter4 Replaceable Parts Firmware Dependent Part Numbers ...
Page 263: ...262 Chapter4 Replaceable Parts Firmware Dependent Part Numbers ...
Page 265: ...264 Chapter4 Replaceable Parts Firmware Dependent Part Numbers ...
Page 267: ...266 Chapter4 Replaceable Parts Firmware Dependent Part Numbers ...
Page 268: ...267 5 Major Assembly and Cable Locations ...
Page 279: ...278 Chapter5 Major Assembly and Cable Locations Introduction Figure 5 9 Front End ...
Page 281: ...280 Chapter5 Major Assembly and Cable Locations Introduction ...
Page 282: ...281 6 General Troubleshooting ...
Page 285: ...284 Chapter6 General Troubleshooting Introduction Figure 6 1 Assembly Test Points ...
Page 286: ...Chapter 6 285 General Troubleshooting Introduction Figure 6 2 Ribbon Cable Connections 1 of 3 ...
Page 287: ...286 Chapter6 General Troubleshooting Introduction Figure 6 3 Ribbon Cable Connections 2 of 3 ...
Page 290: ...Chapter 6 289 General Troubleshooting Introduction Figure 6 5 Service Cal Data Menu ...
Page 331: ...330 Chapter6 General Troubleshooting Block Diagram Description Figure 6 6 Functional Sections ...
Page 343: ...342 Chapter6 General Troubleshooting Block Diagram Description ...
Page 345: ...344 Chapter6 General Troubleshooting Block Diagram Description ...
Page 347: ...346 Chapter6 General Troubleshooting Block Diagram Description ...
Page 349: ...348 Chapter6 General Troubleshooting Block Diagram Description ...
Page 351: ...350 Chapter6 General Troubleshooting Block Diagram Description ...
Page 353: ...352 Chapter6 General Troubleshooting Block Diagram Description ...
Page 354: ...353 7 ADC Interface Section ...
Page 406: ...405 8 IF Section ...
Page 436: ...Chapter 8 435 IF Section A5 IF Assembly Figure 8 3 IF Adjust Signature ...
Page 437: ...436 Chapter8 IF Section A5 IF Assembly Figure 8 4 Detailed IF Adjust Signature 1 ...
Page 438: ...Chapter 8 437 IF Section A5 IF Assembly Figure 8 5 Detailed IF Adjust Signature 2 ...
Page 439: ...438 Chapter8 IF Section A5 IF Assembly Figure 8 6 Detailed IF Adjust Signature 3 ...
Page 440: ...Chapter 8 439 IF Section A5 IF Assembly Figure 8 7 Detailed IF Adjust Signature 4 ...
Page 441: ...440 Chapter8 IF Section A5 IF Assembly Figure 8 8 Detailed IF Adjust Signature 5 ...
Page 443: ...442 Chapter8 IF Section A5 IF Assembly Figure 8 9 Noisy Signature ...
Page 444: ...Chapter 8 443 IF Section A5 IF Assembly Figure 8 10 Noise with Correct Shape ...
Page 445: ...444 Chapter8 IF Section A5 IF Assembly Figure 8 11 Region B Amplitude Variation ...
Page 447: ...446 Chapter8 IF Section A5 IF Assembly Figure 8 13 Faulty Crystal Short ...
Page 463: ...462 Chapter8 IF Section Cal Oscillator Assembly P O A4 ...
Page 465: ...464 Chapter8 IF Section Cal Oscillator Assembly P O A4 ...
Page 467: ...466 Chapter8 IF Section Cal Oscillator Assembly P O A4 ...
Page 469: ...468 Chapter8 IF Section Cal Oscillator Assembly P O A4 ...
Page 470: ...469 9 Controller Section ...
Page 486: ...Chapter 9 485 Controller Section Display Problems 8560E Figure 9 10 Delta Y Waveform ...
Page 503: ...502 Chapter9 Controller Section Keyboard Problems ...
Page 505: ...504 Chapter9 Controller Section Keyboard Problems ...
Page 506: ...505 10 Synthesizer Section ...
Page 577: ...576 Chapter10 Synthesizer Section A21 OCXO ...
Page 579: ...578 Chapter10 Synthesizer Section A21 OCXO ...
Page 581: ...580 Chapter10 Synthesizer Section A21 OCXO ...
Page 582: ...581 11 RF Section ...
Page 598: ...Chapter 11 597 RF Section A14 Frequency Control Assembly Figure 11 2 A7 LODA Drive ...
Page 617: ...616 Chapter11 RF Section A10 Tracking Generator Option 002 ...
Page 618: ...617 12 Display Power Supply Section ...
Page 651: ...650 Chapter12 Display Power Supply Section A6 Power Supply Assembly ...
Page 653: ...652 Chapter12 Display Power Supply Section A6 Power Supply Assembly ...
Page 654: ...653 13 Component Level Information Packets ...
Page 660: ...Chapter 13 659 Component Level Information Packets Introduction ...