Chapter 8
401
ADC/Interface Section
A3 Assembly Video Circuits
2. Refer to
and check for correct logic levels at A3U108 pins 1,
15, and 16. Check for proper output signals at TP6. If the select lines
are not changing, suspect the ADC ASM or the VGA/ADC MUX
Control. If the select lines are changing, but the proper video inputs
are not being switched to the output, replace U108. In SAMPLE
mode, the input is MOD_VIDEO (pin 7); in POS PEAK mode, the
input is POS_PEAK (pin 5); and in NEG PEAK mode, the input is
NEG_PEAK (pin 6).
3. Check for the presence of the YTO ERR signal at A3J2 pin 42 with
an oscilloscope probe.
4. If ERR 300 YTO UNLK or 301 YTO UNLK occurs and the voltage is
near zero during a sweep and positive during retrace (YTO is being
locked), the fault is on the A3 assembly. If a constant dc voltage is
present, refer to the Synthesizer section troubleshooting procedure
in Chapter 11.
5. Set the spectrum analyzer to the following settings:
Span ............................................................................. 5 MHz
Sweep time .................................................................... 50 ms
6. Check for the presence of the SCAN RAMP signal by connecting an
oscilloscope probe to A3J2 pin 45 (component side of A3J2). Connect
the negative-probe lead to A3TP4.
7. A 0 to 10 V ramp should be present in both LINE and FREE RUN
trigger modes. If the waveform is present only in LINE trigger, ADC
control signal HBADC_CLK0 may be faulty. Refer to
8. If the scan ramp is present, but is not being switched to the output of
U108, replace U108. If the scan ramp is absent in either mode, do
the following:
a. Connect the oscilloscope probe to A3J400 pin 15 (HSCAN).
b. A TTL signal (high during 50 ms sweep time and low during
retrace) should be present, indicating A3 is working properly.
Refer to the Synthesizer section troubleshooting procedure in
Chapter 11. A faulty TTL signal indicates a bad A3 Interface
assembly.
Table 8-8
Logic Levels at A3U108
Detector
Mode
U108 pin 1
U108 pin 15
U108 pin 16
SAMPLE
H
L
H
POS PEAK
H
L
L
NEG PEAK
L
L
H
Содержание 8564EC
Страница 17: ...25 1 General Information ...
Страница 37: ...47 2 Adjustment Diagnostic Software ...
Страница 55: ...Chapter 2 65 Adjustment Diagnostic Software 2 LO Frequency Figure 2 2 LO Frequency Adjustment Locations ...
Страница 57: ...Chapter 2 67 Adjustment Diagnostic Software 3 YTO FM Coil Figure 2 3 YTO FM Coil Adjustment Locations ...
Страница 77: ...89 3 Manual Adjustment Procedures ...
Страница 129: ...161 3a Manual Adjustment Procedures 3335A Source not Available ...
Страница 142: ...175 4 Assembly Replacement ...
Страница 151: ...184 Chapter4 Assembly Replacement Procedure 2 A1 Front Frame A18 LCD Figure 4 2 LCD Assembly Exploded View ...
Страница 163: ...Chapter 4 205 Assembly Replacement Procedure 5 A2 A3 A4 and A5 Assemblies Figure 4 10 Assembly Cables 2 of 3 ...
Страница 166: ...208 Chapter4 Assembly Replacement Procedure 5 A2 A3 A4 and A5 Assemblies Figure 4 14 GPIB and A1A1 W1 Cable Placement ...
Страница 168: ...210 Chapter4 Assembly Replacement Procedure 6 A6 Power Supply Assembly Figure 4 15 Power Supply Cover ...
Страница 176: ...226 Chapter4 Assembly Replacement A9 Input Attenuator Figure 4 22 A9 and A10 A12 Mounting Screws ...
Страница 179: ...Chapter 4 229 Assembly Replacement A11 YTO Figure 4 23 A11 Mounting Screws at Right Side Frame ...
Страница 183: ...Chapter 4 233 Assembly Replacement Procedure 8 A14 and A15 Assemblies Figure 4 25 A14 and A15 Assembly Cables ...
Страница 190: ...Chapter 4 243 Assembly Replacement Procedure 11 Rear Frame Rear Dress Panel Figure 4 29 A6 Power Supply Cover ...
Страница 194: ...Chapter 4 257 Assembly Replacement Procedure 13 A21 OCXO Figure 4 34 A21 OCXO Mounting Screws ...
Страница 196: ...259 5 Replaceable Parts ...
Страница 218: ......
Страница 219: ......
Страница 220: ......
Страница 221: ......
Страница 222: ......
Страница 223: ......
Страница 224: ...303 6 Major Assembly and Cable Locations ...
Страница 228: ...Chapter 6 307 Major Assembly and Cable Locations Introduction Figure 6 2 Top View A2 and A3 Unfolded ...
Страница 229: ...308 Chapter6 Major Assembly and Cable Locations Introduction Figure 6 3 Top View A2 A3 A4 and A5 Unfolded ...
Страница 230: ...310 Chapter6 Major Assembly and Cable Locations Introduction Figure 6 5 Bottom View A15 Unfolded ...
Страница 231: ...Chapter 6 311 Major Assembly and Cable Locations Introduction Figure 6 6 Bottom View A15 and A14 Unfolded ...
Страница 233: ...314 Chapter6 Major Assembly and Cable Locations Introduction Figure 6 9 Rear View FL4 B1 BT1 A20 VGA Connector ...
Страница 234: ...315 7 General Troubleshooting ...
Страница 238: ...Chapter 7 319 General Troubleshooting Introduction Figure 7 2 Ribbon Cable Connections 1 of 3 ...
Страница 239: ...320 Chapter7 General Troubleshooting Introduction Figure 7 3 Ribbon Cable Connections 2 of 3 ...
Страница 242: ...Chapter 7 323 General Troubleshooting Introduction Figure 7 5 Service Cal Data Menu ...
Страница 271: ...352 Chapter7 General Troubleshooting Block Diagram Description Figure 7 6 Functional Sections ...
Страница 283: ...364 Chapter7 General Troubleshooting Block Diagram Description ...
Страница 284: ......
Страница 285: ......
Страница 286: ......
Страница 287: ...377 8 ADC Interface Section ...
Страница 291: ...Chapter 8 381 ADC Interface Section Introduction Figure 8 2 A3 Test Connector Pin Locations ...
Страница 321: ......
Страница 322: ...427 9 IF Section ...
Страница 356: ...Chapter 9 461 IF Section A5 IF Assembly Figure 9 13 Detailed IF Adjust Signature 5 ...
Страница 358: ...Chapter 9 463 IF Section A5 IF Assembly Figure 9 14 Noisy Signature Figure 9 15 Noise with Correct Shape ...
Страница 359: ...464 Chapter9 IF Section A5 IF Assembly Figure 9 16 Region B Amplitude Variation Figure 9 17 Region B Amplitude Offset ...
Страница 369: ...474 Chapter9 IF Section Cal Oscillator P O A4 Assembly Figure 9 21 Output Waveform 10 kHz Resolution Bandwidth ...
Страница 370: ...Chapter 9 475 IF Section Cal Oscillator P O A4 Assembly Figure 9 22 Output Waveform 3 kHz Resolution Bandwidth ...
Страница 371: ...476 Chapter9 IF Section Cal Oscillator P O A4 Assembly Figure 9 23 Output Waveform 1 kHz Resolution Bandwidth ...
Страница 372: ...Chapter 9 477 IF Section Cal Oscillator P O A4 Assembly Figure 9 24 Output Waveform 300 Hz Resolution Bandwidth ...
Страница 376: ......
Страница 377: ......
Страница 378: ......
Страница 379: ...487 10 Controller Section ...
Страница 394: ...521 11 Synthesizer Section ...
Страница 431: ...564 Chapter11 Synthesizer Section Unlocked Fractional N PLL Figure 11 8 VCO Bias Voltages for A14 Assemblies ...
Страница 447: ...Chapter 11 581 Synthesizer Section Sweep Generator Circuit Figure 11 11 Simplified Synthesizer Section ...
Страница 448: ...582 Chapter11 Synthesizer Section Sweep Generator Circuit Figure 11 12 Simplified A14 Assembly Block Diagram ...
Страница 451: ......
Страница 452: ......
Страница 453: ......
Страница 454: ...593 12 RF Section ...
Страница 475: ...614 Chapter12 RF Section A14 Frequency Control Assembly Figure 12 4 A7 LO Multiplier Amplifier Drive ...
Страница 489: ...628 Chapter12 RF Section A15 RF Assembly Figure 12 10 10 MHz TTL Reference at U304 Pin 13 ...
Страница 491: ......
Страница 492: ...633 13 Display Power Supply Section ...
Страница 504: ......
Страница 505: ...671 14 Component Level Information Packets ...
Страница 507: ......