Chapter 12
647
Display/Power Supply Section
A6 Power Supply Assembly
Blanking Signal (8560E)
1. Connect an oscilloscope probe to A2J202 pin 3. Connect the
oscilloscope ground lead to TP3. Set the oscilloscope to the following
settings:
Sweep time ................................................................ 2 ms/div
Vertical scale ................................................................. 1 V/div
2. If a 4 Vp-p signal is not seen, the A2 controller assembly is faulty.
3. Repeat steps 1 and 2 with the oscilloscope probe on A2J202 pin 14.
4. Set the oscilloscope to the following settings:
Sweep time ................................................................. 1
µ
s/div
Vertical scale .................................................................. 2 V/div
5. Connect the positive probe lead to A2J202 pin 15. This is the
blanking output.
6. TTL-level pulses should be observed. If the signal is either always
high or always low, the display will be blanked; suspect the A2
controller assembly.
7. If the signals on A2J202 pins 3, 14, and 15 are correct, troubleshoot
the A17 CRT driver.
Buck Regulator Control
See function block H of the A6 power supply schematic diagram in the
component-level information binder.
The buck regulator control pulse-width modulates the buck regulator
and provides a synchronized signal to the DC-DC converter control
circuitry. The buck regulator control has two feedback paths. The first is
the output of the buck regulator, which provides coarse regulation. The
second is the feedback circuit which samples and compares the +5 Vdc
output of the output rectifier.
U202B and associated circuitry senses the output of the input rectifier
and will turn off U203 if the voltage at TP108 is less than
approxi170 Vdc. Also, it will not allow U203 to start up until
this voltage e215 Vdc. A low on the output of U202B will also
clear the overcurrent latch in the DC-DC converter control circuitry.
Thermal shutdown occurs when RT201, mounted on the main heatsink,
reaches a temperature of 100 C. When this occurs, the voltage at U203
pin 13 exceeds 0.6 V and inhibits pulses to the buck regulator.
R203, R204, U211, and associated circuitry provide feedforward for
U203. This makes the loop gain independent of input line voltage and
cancels 120 Hz ripple by more than 10 dB.
U202C and its associated circuitry permit the power supply to start up
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 ...