Chapter 12
12-7
Theory of Operation
Power Supply Theory
Preregulated Voltages
The switching preregulator converts the line voltage to several DC voltages. The regulated
+5 V digital supply goes directly to the motherboard. The following partially regulated
voltages are routed through A15W1 to the A8 post regulator for final regulation:
+70 V (not used) +25 V +18 V
−
18 V +8 V
−
8 V
Reg5 V Digital Supply
The +5 VD supply is regulated by the control circuitry in the A15 preregulator. It goes
directly to the motherboard, and from there to all assemblies requiring a low noise digital
supply. A +5 V sense line returns from the motherboard to the A15 preregulator. The +5 V
CPU is derived from the +5 VD in the A8 post regulator and goes directly to the A19
graphics system processor.
In order for the preregulator to function, the +5 V digital supply must be loaded by one or
more assemblies, and the +5 V sense line must be working. If not, the other preregulated
voltages will not be correct.
Shutdown Indications: the Green LED and Red LED
The green LED is on in normal operation. It is off when line power is not connected, not
switched on, or set too low, or if the line fuse has blown.
The red LED, which is off in normal operation, turns on to indicate a fault in the +5 V
supply. This may be an over/under line voltage, over line current, or overtemperature
condition. Refer to the troubleshooting chapters for more information.
A8 Post Regulator
The A8 post regulator filters and regulates the DC voltages received from the A15
preregulator. It provides fusing and shutdown circuitry for individual voltage supplies. It
distributes regulated constant voltages to individual assemblies throughout the
instrument. It includes the overtemperature shutdown circuit, the variable fan speed
circuit, and the air flow detector. Nine green LEDs provide status indications for the
individual voltage supplies.
Refer to the power supply block diagram located at the end of
to see the voltages provided by the A8 post regulator.
Voltage Indications: the Green LEDs
The nine green LEDs along the top edge of the A8 assembly are on during normal
operation, to indicate the correct voltage is present in each supply. If they are off or
flashing, a problem is indicated. The troubleshooting procedures (later in this chapter)
detail the steps to trace the cause of the problem.
Содержание 8753ES
Страница 14: ...Contents xiv Contents ...
Страница 15: ...1 1 1 Service Equipment and Analyzer Options ...
Страница 26: ...1 12 Chapter1 Service Equipment and Analyzer Options Service and Support Options ...
Страница 27: ...2 1 2 System Verification and Performance Tests ...
Страница 202: ...2 176 Chapter2 System Verification and Performance Tests Agilent 8753ET Performance Test Records ...
Страница 203: ...3 1 3 Adjustments and Correction Constants ...
Страница 262: ...3 60 Chapter3 Adjustments and Correction Constants Sequences for Mechanical Adjustments ...
Страница 263: ...4 1 4 Start Troubleshooting Here ...
Страница 297: ...5 1 5 Power Supply Troubleshooting ...
Страница 305: ...Chapter 5 5 9 Power Supply Troubleshooting If the Red LED of the A15 Is ON Figure 5 5 Power Supply Cable Locations ...
Страница 317: ......
Страница 318: ...6 1 6 Digital Control Troubleshooting ...
Страница 337: ...6 20 Chapter6 Digital Control Troubleshooting GPIB Failures ...
Страница 338: ...7 1 7 Source Troubleshooting ...
Страница 369: ...7 32 Chapter7 Source Troubleshooting Source Group Troubleshooting Appendix ...
Страница 370: ...8 1 8 Receiver Troubleshooting ...
Страница 381: ...8 12 Chapter8 Receiver Troubleshooting Troubleshooting When One or More Inputs Look Good ...
Страница 382: ...9 1 9 Accessories Troubleshooting ...
Страница 389: ...9 8 Chapter9 Accessories Troubleshooting Inspect the Error Terms ...
Страница 390: ...10 1 10 Service Key Menus and Error Messages ...
Страница 439: ...10 50 Chapter10 Service Key Menus and Error Messages Error Messages ...
Страница 440: ...11 1 11 Error Terms ...
Страница 451: ...11 12 Chapter11 Error Terms Error Correction ...
Страница 452: ...12 1 12 Theory of Operation ...
Страница 461: ...12 10 Chapter12 Theory of Operation Digital Control Theory Figure 12 3 Digital Control Group Simplified Block Diagram ...
Страница 482: ...13 1 13 Replaceable Parts ...
Страница 487: ...13 6 Chapter13 Replaceable Parts Ordering Information Figure 13 1 Module Exchange Procedure ...
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Страница 492: ...Chapter 13 13 11 Replaceable Parts Replaceable Part Listings Figure 13 2 8753ET Major Assemblies Top ...
Страница 494: ...Chapter 13 13 13 Replaceable Parts Replaceable Part Listings Figure 13 3 8753ES Major Assemblies Top ...
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Страница 500: ...Chapter 13 13 19 Replaceable Parts Replaceable Part Listings Figure 13 7 8753ET Cables Top ...
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Страница 506: ...Chapter 13 13 25 Replaceable Parts Replaceable Part Listings Figure 13 10 8753ET Cables Bottom ...
Страница 508: ...Chapter 13 13 27 Replaceable Parts Replaceable Part Listings Figure 13 11 8753ES Cables Bottom ...
Страница 510: ...Chapter 13 13 29 Replaceable Parts Replaceable Part Listings Figure 13 12 8753ET Cables Front 8753ET Option 004 ...
Страница 512: ...Chapter 13 13 31 Replaceable Parts Replaceable Part Listings Figure 13 13 8753ES Cables Front ...
Страница 514: ...Chapter 13 13 33 Replaceable Parts Replaceable Part Listings Figure 13 14 8753ET ES Cables Rear ...
Страница 518: ...Chapter 13 13 37 Replaceable Parts Replaceable Part Listings Figure 13 17 8753ET ES Front Panel Assembly Outside ...
Страница 520: ...Chapter 13 13 39 Replaceable Parts Replaceable Part Listings Figure 13 18 8753ET ES Front Panel Assembly Inside ...
Страница 522: ...Chapter 13 13 41 Replaceable Parts Replaceable Part Listings Figure 13 19 8753ET Rear Panel Assembly ...
Страница 524: ...Chapter 13 13 43 Replaceable Parts Replaceable Part Listings Figure 13 20 8753ES Rear Panel Assembly ...
Страница 526: ...Chapter 13 13 45 Replaceable Parts Replaceable Part Listings Figure 13 21 8753ET ES Rear Panel Assembly Option 1D5 ...
Страница 528: ...Chapter 13 13 47 Replaceable Parts Replaceable Part Listings Figure 13 22 8753ET ES Hardware Top ...
Страница 538: ...Chapter 13 13 57 Replaceable Parts Replaceable Part Listings Figure 13 31 8753ET ES Chassis Parts Outside ...
Страница 544: ...14 1 14 Assembly Replacement and Post Repair Procedures ...
Страница 550: ...Chapter 14 14 7 Assembly Replacement and Post Repair Procedures Covers Figure 14 2 Covers ...
Страница 552: ...Chapter 14 14 9 Assembly Replacement and Post Repair Procedures Front Panel Assembly Figure 14 3 Front Panel Assembly ...
Страница 558: ...Chapter 14 14 15 Assembly Replacement and Post Repair Procedures Rear Panel Assembly Figure 14 6 Rear Panel Assembly ...
Страница 562: ...Chapter 14 14 19 Assembly Replacement and Post Repair Procedures A3 Source Assembly Figure 14 8 A3 Source Assembly ...
Страница 568: ...Chapter 14 14 25 Assembly Replacement and Post Repair Procedures A9 CPU Board Figure 14 11 A9 CPU Board ...
Страница 570: ...Chapter 14 14 27 Assembly Replacement and Post Repair Procedures A9BT1 Battery Figure 14 12 A9BT1 Battery ...
Страница 572: ...Chapter 14 14 29 Assembly Replacement and Post Repair Procedures A15 Preregulator Figure 14 13 A15 Preregulator ...
Страница 588: ...Chapter 14 14 45 Assembly Replacement and Post Repair Procedures A23 LED Board 8753ES Only Figure 14 20 A23 LED Board ...
Страница 597: ...14 54 Chapter14 Assembly Replacement and Post Repair Procedures Post Repair Procedures ...
Страница 598: ...15 1 15 Safety and Regulatory Information ...