FLUKE 45 电路图.pdf

45 Dual Display Multimeter Service Manual For IEC 1010 Meters Only PN 609203 March 1999 Rev.1, 1/04 1999-2004 Fluke Corporation, All rights reserved. Printed in U.S.A. All product names are trademarks of their respective companies. RadioFans.CN 收音机爱 好者资料库 LIMITED WARRANTY effective troubleshooting may require not only reference to the troubleshooting procedures in Chapter 5, but also some understanding of the detailed Theory of Operation in Chapter 2 and some tracing of circuit operation in the Schematic Diagrams presented in Chapter 9. Often, scanning the table of contents will yield an appropriate place to start using the manual. A comprehensive table of contents is presented at the front of the manual; local tables of contents are also presented at the beginning of each chapter for ease of reference. If you know the topic name, the index at the end of the manual is probably a good place to start. The following chapter descriptions serve to introduce the manual: Chapter 1. Introduction and Specifications Introduces the Fluke 45 Dual Display Multimeter, describing its features, options, and accessories. This chapter also discusses use of the Service Manual and the various conventions used in describing the meters circuitry. Finally, a complete set of specifications is presented. Introduction and Specifications Conventions1 1-5 Chapter 2. Theory of Operation This chapter first categorizes meter circuitry into functional blocks, with a description of each blocks role in overall operation. A detailed circuit description is then given for each block. These descriptions explore operation to the component level and fully support troubleshooting procedures defined in Chapter 5. Chapter 3. General Maintenance Provides maintenance information covering handling, cleaning, and fuse replacement. Access and reassembly procedures are also explained in this chapter. Chapter 4. Performance Testing and Calibration This chapter provides performance verification procedures that are tied to the specifications presented in Chapter 1. To maintain these specifications, a full calibration procedure is also presented. Chapter 5. Diagnostic Testing and Troubleshooting The troubleshooting procedures presented in this chapter rely closely on both the Theory of Operation presented in Chapter 2 and the Schematic Diagrams shown in Chapter 9. Chapter 3 provides access information. Chapter 6. List of Replaceable Parts Includes parts lists for all standard assemblies. Information on how and where to order parts is also provided. Chapter 7. Option -01 Battery Pack Each option is allocated a separate chapter: 7 for the Battery Pack Option -01 and 8 for the IEEE-488 Interface Option -05. Option -15 incorporates both Options -01 and -05. Chapter 7 includes the full range of Service Manual topics (specifications, theory of operation, maintenance, list of replaceable parts, etc.) for the Battery Pack option. Schematic diagrams for the options are found in Chapter 9. Chapter 8. Option -05 IEEE-488 Interface Includes the full range of Service Manual topics (specifications, theory of operation, maintenance, list of replaceable parts, etc.) for the IEEE-488 Interface option. Schematic diagrams for the options are found in Chapter 9. Chapter 9. Schematic Diagrams Includes schematic diagrams for all standard and optional assemblies. A list of mnemonic definitions is also included to aid in identifying signal name abbreviations. 1-5. Conventions Throughout the manual set, certain notational conventions are used. A summary of these conventions follows: Instrument Reference The Fluke 45 Dual Display Multimeter is usually called the meter. Printed Circuit Assembly 45 Service Manual 1-6 The term pca is used to represent a printed circuit assembly and its attached parts. Signal Logic Polarity On schematic diagrams, a signal name followed by a * is active (or asserted) low. Signals not so marked are active high. Circuit Nodes Individual pins or connections on a component are specified with a dash (-) following the component reference designator. For example, pin 19 of U30 would be U30-19. User Notation For front panel operation, XXXAn uppercase word or symbol without parentheses indicates a button to be pressed by the user. Buttons can be pressed in four ways: 1. Press a single button to select a function or operation. 2. Press a combination of buttons, one after the other. 3. Press and hold down a button, then press another button. 4. Press multiple buttons simultaneously. For computer interface operation, XXXAn uppercase word without parentheses identifies a command by name. Angle brackets around all uppercase letters mean press the key. (xxx)When associated with a keyword, a lowercase word in parentheses indicates an input required by the user. 1-6. Specifications The following contains the specifications for the Fluke 45 Dual Display Multimeter. These specifications assume: A 1-year calibration cycle An operating temperature of 18 to 28C Relative humidity not exceeding 90% (non-condensing) Accuracy is expressed as (percentage of reading + counts). Reading Rates and Display Counts RateReadings per SecondFull Range Display Counts Slow Medium Fast 2.5 5 20 99,999* 30,000 3,000 * Ohms full range will typically be 98,000 counts Introduction and Specifications Specifications1 1-7 Response Times Refer to Chapter 4 of the Users Manual for detailed information. DC Voltage ResolutionAccuracy Range SlowMediumFast(6 months)(1 year) 300 mV 3 V 30 V 300 V 1000 V - - - - - 10 V 100 V 1 mV 10 mV 100 mV 100 V 1 mV 10 mV 100 mV 1 V 0.02% + 2 0.02% + 2 0.02% + 2 0.02% + 2 0.02% + 2 0.025%+2 0.025% +2 0.025%+2 0.025% +2 0.025%+2 100 mV 1000 mV 10 V 100 V 1000 V 1 V 10 V 100 V 1 mV 10 mV - - - - - - - - - - 0.02% + 6 0.02% + 6 0.02% + 6 0.02% + 6 0.02% + 6 0.025%+6 0.025% +6 0.025%+6 0.025% +6 0.025%+6 Input Impedance 10 M in parallel with 80 dB at 50 or 60 Hz, slow and medium rates 54 dB for frequencies between 50-440 Hz, slow and medium rates 60 dB at 50 Hz, fast rate (Note: Fast rate has no filtering) Maximum Allowable AC Voltage While Measuring DC Voltage Peak Normal Mode Signal RangeMax Allowable Peak AC Voltage NMRR* 80dB*NMRR 60 dB* 300 mV100 mV20 V15 V15 V 3 V1000 mV20 V15 V15 V 30 V10 V1000 V50 V300 V 300 V100 V1000 V50 V300 V 1000 V1000 V1000 V200 V1000 V * NMRR is the Normal Mode Rejection Ratio * Normal Mode Rejection Ratio at 50 or 60 Hz 0.1% Common Mode Rejection Ratio 90 dB at dc, 50 or 60 Hz, (1 k unbalanced, medium and slow rates) 45 Service Manual 1-8 Maximum Functional Input 1000 V dc or peak ac on any range True Rms AC Voltage, AC-Coupled Range Resolution SlowMediumFast 300 mV-10 V100 V 3 V-100 V1 mV 30 V-1 mV10 mV 300 V-10 mV100 mV 750 V-100 mV1 V 100 mV1 V- 1000 mV10 V- 10 V100 V- 100 V1 mV- 750 V10 mV- Accuracy FrequencyLinear AccuracydB AccuracyPower* Max Input at Upper Freq SlowMediumFastSlow/MedFast 20-50 Hz1% + 1001% + 107% + 20.150.722% + 10750 V 50 Hz -10 kHz0.2% + 1000.2% + 100.5% + 2 0.080.170.4% + 10 750 V 10 - 20 kHz0.5% + 1000.5% + 100.5% + 2 0.110.171% + 10750 V 20 - 50 kHz2% + 2002% + 202% + 30.290.344% + 20400 V 50 - 100 kHz5% + 5005% + 505% + 60.700.7810% + 50200 V * Error in power mode will not exceed twice the linear accuracy specification Accuracy specifications apply within the following limits, based on reading rate: Slow Reading Rate:Between 15,000 and 99,999 counts (full range) Medium Reading Rate:Between 1,500 and 30,000 counts (full range) Fast Reading Rate:Between 150 and 3,000 counts (full range) Decibel Resolution Resolution Slow treat it as you would any other conducting surface. On the bottom of the Main PCA, the Analog Measurement Processor is protected with a metallic shield. Access the Analog Measurement Processor with the following procedure: 45 Service Manual 3-10 Working from the bottom of the Main PCA, remove the single Phillips head screw (J in Figure 3-6) securing the metallic shield, then lift the plastic shield (M) away from the top of the Main PCA. If necessary, remove the metallic shield (K.) Avoid contacting any circuit traces during this procedure. First rotate the shield toward the pca edge, then pry the shield free from its nylon standoff (L). 3-22. Remove the Rms PCA The rms pca is soldered in place on the Main PCA (within the Analog Measurement Processor shield.) For access procedures, refer to Remove the Analog Measurement Processor Shields. Use standard desoldering techniques (e.g. solder sucker or solder wick) when removing this assembly. 3-23. Remove the Battery Option Use the following procedure to remove the Battery Option. Refer to Figures 7-2 and 7-3 (Chapter 7) to identify features and techniques mentioned here. If necessary, refer to Chapter 7 for a detailed description of Battery Option removal. 1. Disconnect the flat white battery option connecting cable at the Battery Option PCA. 2. Remove the two #6-32 x 1/4 panhead Phillips screws securing the Battery Option. 3. Carefully slide the Battery Option out of the meter. Do not pinch the wires running from the pca to the battery terminals. 3-24. Disconnect Miscellaneous Chassis Components The following procedures can be used to disconnect remaining hardware from the chassis: 1. Use needle nose pliers to remove the internal connections at the line power plug. 2. Remove the power plug by releasing its two snaps, one at a time. 3. Disconnect the power transformer by removing the four screws (N in Figure 3-5) that secure it to the right side of the chassis. 4. Remove the RS-232 connector (O) on the rear of the chassis. Use a 3/16-inch nut driver to loosen the connector securing hardware. Also, disconnect the ground wire at its chassis connection. 5. Remove the IEEE connector. 3-25. Assembly Procedures Generally, assembly procedures follow a reverse sequence of disassembly procedures. As some differences do apply, assembly is described separately in the following paragraphs. Begin assembly at the appropriate level, as defined by the heading. References are made to items in Figure 3-5 for assembly details of standard meter parts. 3-26. Install Miscellaneous Chassis Components Use the following procedure to replace any items that have been removed from the basic chassis. 1. Install the IEEE connector on the rear of the chassis. General Maintenance Assembly Procedures3 3-11 2. Replace the RS-232 connector (O) on the rear of the chassis. Use a 3/16-inch nut driver to tighten the connector hardware. Also, attach the ground wire at its chassis connection. 3. Replace the power transformer along the right side of the chassis. Use four 6-32 x .25 FHU screws (N), inserted from the exterior of the meter. 4. Snap the power plug into position. 5. Use needle nose pliers to replace the interior connections at the power plug. 3-27. Install the Battery Option Installation is fully described in both the instruction sheet supplied with the Battery Option and in Chapter 7 of this manual. The following procedure presents installation essentials. Figures 7-2 and 7-3 can be used in identifying features and techniques mentioned here. 1. Carefully slide the battery kit into the area reserved for it in the back of the meter. Make sure that both the retaining slots line up and the mounting holes mate. Do not pinch wires running from the circuit assembly to the battery terminals. 2. Secure the battery kit with two #6-32 x 1/4 panhead Phillips screws. 3. Attach the flat, white connecting cable at the Battery Option PCA. The single blue marking line of the cable should be to the rear of the meter. Align the plastic socket on the cable end, then seat it securely in place. 3-28. Install the Rms PCA With the Analog Measurement Processor shields removed, solder the Rms PCA into place on the upper side of the Main PCA. The component side of the Rms PCA faces forward. 3-29. Install the Analog Measurement Processor Shields The Analog Measurement Processor resides within a plastic shield on the top of the Main PCA. Although having the appearance of a dark gray piece of plastic, this shield is electrically conductive; treat it as you would any other conducting surface. On the bottom of the Main PCA, the Analog Measurement Processor is protected with a metallic shield. Press the conductive plastic shield (M) into place on the top of the Main PCA. From the bottom of the Main PCA, install the metallic shield (K.) Avoid contacting any circuit traces during this procedure. Then replace the single Phillips head screw (J) securing the metallic shield. 3-30. Install the Main PCA 1. Prior to installing the Main PCA, verify the following: If necessary, reinstall the transformer insulator (I), tabs down, around the right side of the transformer. Once the insulator is in place, pull each tab through the Main PCA from bottom side with a needle nose pliers. If the nylon standoff (L) used between the Main PCA and the metallic shield surrounding the Analog Measurement Processor has been removed, verify that proper orientation is maintained during installation. The standoff end with the shorter, beveled indent fits into the metallic shield. Press the standoff end with the wider, straighter indent into the Main PCA with a 3/16 nut driver. 45 Service Manual 3-12 2. Ensure that the nylon standoff support (front-center of the Main PCA) is in place. Then slide the Main PCA onto the chassis slider taps. 3. Fasten the Main PCA to the chassis with a 6-32, 1/4-inch panhead screw (H). 4. Connect the transformer cable (F) and RS-232 cable (G) at the Main PCA. 3-31. Install the IEEE-488 Option Both the instruction sheet provided with the IEEE-488 Option and Chapter 8 of this manual fully describe installation. The following instructions provide installation procedure essentials. If necessary, refer to Chapter 8, paying particular attention to Figures 8-2 and 8-3. 1. Check that the plastic standoff remains in the appropriate hole in the Main PCA (narrow end of the standoff down.) 2. If necessary, install the two ribbon cables on the IEEE-488 circuit board. Each cable fits in only one socket and in only one direction. Make sure the cables lock firmly in place. 3. Attach opposite ends of the ribbon cables onto the Fluke 45 Main PCA. 4. Install the IEEE-488 PCA into the small slot in the side of the Fluke 45 (two ribbon cables facing forward.) The end of the plastic standoff fits into the hole in the IEEE- 488 PCA. Make sure the IEEE-488 PCA is firmly gripped against the retainer on the standoff and that the rear of the pca rests upon the support just forward of the transformer. 5. Secure the rear of the IEEE-488 PCA with the panhead Phillips screw. 6. Connect the 24-line cable assembly to the IEEE-488 circuit board. 3-32. Assemble the Front Panel Assembly As appropriate, use the following steps to assemble the Front Panel Assembly. 1. Clean the lens (D) with deionized air and, if necessary, isopropyl alcohol. Then gently snap the lens into the front panel tabs. 2. Install the elastomeric keypad