® 51, 52, 53, 54 Series II Thermometer Service Manual PN 1276123 October 1999 © 1999 Fluke Corporation. All rights reserved. Printed in USA All product names are trademarks of their respective companies.
LIMITED WARRANTY & LIMITATION OF LIABILITY Each Fluke product is warranted to be free from defects in material and workmanship under normal use and service. The warranty period is three years and begins on the date of shipment. Parts, product repairs and services are warranted for 90 days.
Table of Contents Title Introduction ....................................................................................................... Service Centers.................................................................................................. International Symbols........................................................................................ Precautions and Safety Information .................................................................. General Specifications .....................
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List of Tables Table 1. 2. 3. 4. Title International Electrical Symbols Used in this Manual........................................... Recommended Test Equipment ............................................................................. Performance Test Values (K-Type Thermocouple)............................................... Replaceable Parts ...................................................................................................
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List of Figures Figure 1. 2. 3. 4. 5. 6. Title Display Segments .................................................................................................. Ice Bath Test Equipment Connections................................................................... Calibration Connections ........................................................................................ Calibration Button Access ..................................................................................... Battery Access ....
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51, 52, 53, 54 Series II Service Manual WWarning To avoid shock or injury, do not perform the performance tests or calibration procedures described in this manual unless you are qualified to do so. Refer to the Safety Information section of this manual before using the Fluke 51, 52, 53, 54 Series II Thermometers. Caution The Fluke 51, 52, 53, 54 Series II Thermometers contain parts that can be damaged by static discharge. Follow the standard practices for handling static sensitive devices.
51, 52, 53, 54 Series II Service Manual Service Centers To contact Fluke, order parts, or locate a Fluke service center, call one of the following telephone numbers: USA: 1-888-99-FLUKE (1-888-993-5853) Canada: 1-800-36-FLUKE (1-800-363-5853) Europe: +31 402-678-200 Japan: +81-3-3434-0181 Singapore: +65-738-5655 Anywhere in the world: +1-425-446-5500 Or, visit Fluke’s Web site at www.fluke.com. International Symbols Table 1 identifies the international electrical symbols used in this manual. Table 1.
Thermometer Precautions and Safety Information Safety Information WWarning To avoid electrical shock or personal injury, follow these guidelines: • Before using the thermometer, inspect the case. Do not use the thermometer if it appears damaged. Look for cracks or missing plastic. Pay particular attention to the insulation around the connectors. • Disconnect the thermocouple(s) from the thermometer before opening the case. • Replace the batteries as soon as the low battery indicator (B) appears.
51, 52, 53, 54 Series II Service Manual Specifications General Specifications Weight Dimensions (without holster) 280 g (10 oz) 2.8 cm × 7.8 cm × 16.2 cm (1.1 in × 3 in × 6.4 in) Battery Certification 3 AA batteries P, ) (TÜV pending) Safety CSA C22.2 No. 1010.1 1992 EN 61010 Amendments 1, 2 CAT I OVERVOLTAGE (Installation) CATEGORY I, Pollution Degree 2 per IEC1010-1* * Refers to the level of Impulse Withstand Voltage protection provided.
Thermometer Performance Test and Calibration Required Test Equipment Performance Test and Calibration Required Test Equipment Refer to Table 2 for a list of test equipment used in the performance test and calibration procedures. Table 2. Recommended Test Equipment Equipment Required Characteristics Output Voltage: 0-1V Accuracy: 0.0125 % Resolution: 0.
51, 52, 53, 54 Series II Service Manual 51 53 54 52 zb03f.eps Figure 1. Display Segments Keypad Test Check that all keypad switches are functional by pressing each key and confirming the proper response on the display. Wide Range Performance Test Procedure This test verifies the instrument specifications. If the instrument fails this test, perform the calibration procedure. If the unit continues to fail, it should be taken to a Fluke service center.
Thermometer Performance Tests 4. Replace the Dewar Flask cap or cork, and insert the thermocouple wires and Mercury thermometer as shown in Figure 2. Insert the Mercury thermometer to the same depth as the thermocouple wire. _ Copper wire _ K-Type Thermocouple wire Mercury Thermometer - + - K-Type Thermocouple connector + 51, 52, 53, or 54 Series II Thermometer + 5700A Calibrator Ice bath - zb04f.eps Figure 2.
51, 52, 53, 54 Series II Service Manual Table 3. Performance Test Values (K-Type Thermocouple) Input Voltage Step Equivalent Temperature (mV DC) Display Reading limits °C °F 1 0.0000 0.0 °C 32.0 °F -0.3 to 0.3 31.5 to 32.5 2 0.9193 23.0 °C 73.4 °F 22.7 to 23.3 72.9 to 73.9 3 -5.7297 -190.0 °C -310.0 °F -189.3 to -190.7 -308.9 to -311.1 4 40.8853 990.0 °C 1814 °F 989.2 to 990.8 1813 to 1815 5 48.
Thermometer Calibration and Offset Adjustment Calibration and Offset Adjustment Calibration consists of two parts: 1. Calibration of the A/D converter, using the set up shown in Figure 3. 2. Reference junction calibration, using the ice bath test set up shown in Figure 2. A/D Calibration To calibrate the A/D portion of the thermometer, follow these steps: 1. Connect the calibrator to the T1 input of the thermometer using copper (nonthermocouple) wire and a copper thermocouple connector.
51, 52, 53, 54 Series II Service Manual Calibration button access zb02f.eps Figure 4. Calibration Button Access 3. The menu on the display changes to “CAL A-d”. Note Within CAL are four menu options that may be accessed by pressing E: • CAL A-d prompts the operator for the A/D calibration inputs in mV dc. • CAL rEF allows the operator to calibrate the reference junction at a known temperature. • CAL donE saves the new calibration constants in memory.
Thermometer Calibration and Offset Adjustment 11. To ignore the calibration changes, use K or N, and select “CAL Abrt” and press E. 12. Proceed to Reference Junction Calibration. Reference Junction Calibration Note This procedure is described using an ice bath and a K-type thermocouple. It can be performed in °C, °F, or K with any thermocouple and a known, accurate temperature between 0 °C (+32 °F) and +50 °C (+122 °F).
51, 52, 53, 54 Series II Service Manual Basic Maintenance Basic maintenance required by the thermometer is discussed in this section. Cleaning the Thermometer • Caution To avoid damaging the thermometer, do not use aromatic hydrocarbons or chlorinated solvents for cleaning. These solutions react with the plastics used in the thermometer. • Do not allow the LCD to get wet. • Do not remove any of the lubricant from the battery/pca connection. Clean the thermometer case with a mild detergent and water.
Thermometer Disassembly and Reassembly zb01f.eps Figure 5. Battery Access Disassembly and Reassembly Disassembly and reassembly of the thermometer may be necessary to replace interior parts. Refer to Figure 6 when disassembling and reassembling the thermometer. Disassembly To disassemble the thermometer, follow these steps: 1. Remove the batteries (see “Changing the Batteries” section). 2. Remove the two screws located inside the battery compartment.
51, 52, 53, 54 Series II Service Manual 6. The LCD decal is now exposed and may be removed. 7. To remove the main switch pad, first remove the small elastomeric connector at the top of the switch pad, and then lift out the entire switch pad. Reassembly The reassembly procedure is basically the reverse of the disassembly procedure. However, there are several points in this process that should be explained further.
Thermometer Replaceable Parts 5. Push the Isothermal PCA and the Main PCA together so that the Isothermal PCA pins go deeper into the Main PCA sockets. This holds the IR Lens in place and allows the Main PCA to be reinstalled into the top case. Reinstalling the Main PCA 1. While holding the IR Lens to the Main PCA, turn the Main PCA over so that the components are facing up. 2. Align the screw holes in the Main PCA with those in the top case. 3. Align the backlight pins with the Main PCA sockets. 4.
51, 52, 53, 54 Series II Service Manual Table 4. Replaceable Parts (cont.) Item Number 9A-B Qty.
Thermometer Replaceable Parts 10 5 11 17 9B 9A 6 15 12 8B 7 16 8C 8E 8F 8D 14 8A 2 1 13 3 4 zb07f.eps Figure 6.
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Index —A— —I— assembly, 13 ice bath construction, 6 equipment connections, 7 test, 7 —B— batteries access to, 13 changing, 12 —C— calibration, 9 A/D, 9 A/D connections, 9 button access, 10 CAL Abrt, 10 CAL A-d, 10 CAL donE, 10 CAL rEF, 10 offset, 9 reference junction, 11 variations between thermocouples, 11 caution, 12, 13 CD ROM, 1 —D— disassembly, 13 display segments, 6 —E— electrical symbols, 2 —H— HyperTerminal, 8 —L— LCD reinstalling, 14 —M— Main PCA rebuilding, 14 reinstalling, 15 maintenan
51, 52, 53, 54 Series II Service Manual —S— safety, 2 cautions and warnings, 3 service centers phone numbers, world wide web address, 2 specifications electrical, 4 environmental, 4 general, 4 —T— test equipment 2 performance testing and calibration, 5 —U— Users Manual 51, 52 Series II, 1 53, 54 Series II, 1 —W— warnings, 1, 12