Fluke IP Phone 51 User Manual

®
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.  
 
Table of Contents  
Title  
Page  
Introduction ....................................................................................................... 1  
Service Centers.................................................................................................. 2  
International Symbols........................................................................................ 2  
Precautions and Safety Information .................................................................. 2  
General Specifications .................................................................................. 4  
Environmental............................................................................................... 4  
Electrical ....................................................................................................... 4  
Performance Test and Calibration Required Test Equipment ........................... 5  
Performance Tests ............................................................................................. 5  
Display Test .................................................................................................. 5  
Keypad Test .................................................................................................. 6  
Wide Range Performance Test Procedure .................................................... 6  
Ice Bath Construction ............................................................................... 6  
Ice Bath Test............................................................................................. 7  
Verification of IR Communications Port (Fluke 53 and 54)......................... 8  
Calibration and Offset Adjustment.................................................................... 9  
A/D Calibration............................................................................................. 9  
Reference Junction Calibration..................................................................... 11  
Using the Offset to Adjust for Variation Between Thermocouples .............. 11  
Basic Maintenance............................................................................................. 12  
Cleaning the Thermometer............................................................................ 12  
Changing the Batteries .................................................................................. 12  
Disassembly and Reassembly............................................................................ 13  
Disassembly .................................................................................................. 13  
Reassembly ................................................................................................... 14  
Reinstalling the LCD Assembly ............................................................... 14  
Rebuilding the Main PCA......................................................................... 14  
Reinstalling the Main PCA....................................................................... 15  
Replaceable Parts............................................................................................... 15  
Index  
i
 
51, 52, 53, 54 Series II  
Service Manual  
ii  
 
List of Tables  
Table  
Title  
Page  
1.  
2.  
3.  
4.  
International Electrical Symbols Used in this Manual........................................... 2  
Recommended Test Equipment............................................................................. 5  
Performance Test Values (K-Type Thermocouple)............................................... 8  
Replaceable Parts................................................................................................... 15  
iii  
 
51, 52, 53, 54 Series II  
Service Manual  
iv  
 
List of Figures  
Figure  
Title  
Page  
1.  
2.  
3.  
4.  
5.  
6.  
Display Segments .................................................................................................. 6  
Ice Bath Test Equipment Connections................................................................... 7  
Calibration Connections ........................................................................................ 9  
Calibration Button Access ..................................................................................... 10  
Battery Access ....................................................................................................... 13  
Exploded View (Model 54 is Shown).................................................................... 17  
v
 
51, 52, 53, 54 Series II  
Service Manual  
vi  
 
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.  
Introduction  
This manual provides the following service information for the 51, 52, 53, and 54 Series  
II Thermometers, hereafter referred to as “the thermometer”.  
Precautions and safety information  
Specifications  
Performance tests  
Calibration and adjustment  
Basic maintenance  
Replaceable parts  
For complete operating instructions, refer to the 51/52 Series II Users Manual or the 53,  
54 Series II Users Manual, located on the 51/54 Series II CD ROM, part number  
1276106.  
1
 
 
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 Flukes Web site at www.fluke.com.  
International Symbols  
Table 1 identifies the international electrical symbols used in this manual.  
Table 1. International Electrical Symbols Used in this Manual  
Low Battery  
Important information  
B
Complies with relevant Canadian Standards  
Association directives  
Complies with European Union  
directives  
Precautions and Safety Information  
Use the thermometer only in the ways specified in the 51/52 Series II Users Manual and  
the 53/54 Series II Users Manual. If the thermometer is used in ways not specified, the  
thermometer may be damaged.  
In this manual, a Warning statement identifies conditions and actions that pose a hazard  
to the user; a Caution statement identifies conditions and actions that may damage the  
thermometer or the test instruments.  
2
 
 
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. The  
possibility of false readings can lead to personal injury.  
Do not use the thermometer if it operates abnormally. Protection may be  
impaired. When in doubt, have the thermometer serviced.  
Do not operate the thermometer around explosive gas, vapor, or dust.  
Do not apply more than the rated voltage, as marked on the thermometer,  
between the thermocouple(s), or between any thermocouple and earth  
ground.  
Models 52 and 54: Measurement errors may occur if voltages on the  
measurement surfaces result in potentials greater than 1 V between the  
two thermocouples. When potential differences are anticipated between  
the thermocouples, use electrically insulated thermocouples.  
When servicing the thermometer, use only specified replacement parts.  
Do not use the thermometer with any part of the case or cover removed.  
Caution  
To avoid damaging the thermometer or the equipment under test:  
Use the proper thermocouples, function, and range for your thermometer.  
Do not attempt to recharge the batteries.  
To prevent explosion, do not dispose of batteries in fire.  
Follow local laws or regulations when disposing of batteries.  
Match the + and polarities of the batteries with the battery case  
markings.  
3
 
 
51, 52, 53, 54 Series II  
Service Manual  
Specifications  
General Specifications  
Weight  
280 g (10 oz)  
Dimensions  
(without holster)  
2.8 cm × 7.8 cm × 16.2 cm  
(1.1 in × 3 in × 6.4 in)  
Battery  
3 AA batteries  
Certification  
Safety  
P,  
(TÜV pending)  
)
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. Equipment of OVERVOLTAGE  
CATEGORY I is equipment for connection to circuits in which measures are taken to limit the transient  
over voltages to an appropriate low level.  
Environmental  
Operating Temperature  
Storage Temperature  
10 oC to +50 oC (+14 oF to +122oF)  
40 oC to +60oC (40 oF to +140 oF)  
Non Condensing (< +10 oC) (< +50 oF)  
95% RH (+10 oC to +30 oC) (+50 oF to +86 oF)  
75% RH (+30 oC to +40 oC) (+86 oF to +104 oF)  
45% RH (+40 oC to +50 oC) (+104 oF to +122 oF)  
(Without Condensation)  
Humidity  
Electrical  
J-type: 210 oC to +1200 oC (346 oF to +2192 oF)  
K-type: 200 oC to +1372 oC (328 oF to +2501 oF)  
T-type: 250 oC to +400 oC (418 oF to +752 oF)  
E-type: 150 oC to +1000 oC (238 oF to +1832 oF)  
N-type: 200 oC to +1300 oC (328 oF to +2372 oF)  
R- and S-type: 0 oC to +1767 oC (+32 oF to +3212 oF)  
Measurement  
Range  
Display  
Resolution  
0.1 oC / oF / K < 1000o  
1.0 oC / oF / K 1000o  
J-, K-, T-, E-, and N-type: ±[0.05 % of reading + 0.3 oC (0.5 oF)]  
[below 100 oC (148 oF): add 0.15 % of reading for J, K, E, and N;  
and 0.45 % of reading for T]  
Measurement  
Accuracy  
R- and S-type: ±[0.05 % of reading + 0.4 oC (+0.7 oF)]  
0.01 % of reading + 0.03 oC per oC  
Temperature  
Coefficient  
(0.05 oF per oF) outside the specified +18 oC to +28 oC (+64 oF to +82 oF) range  
[below 100 oC (148 oF): add 0.04 % of reading for J-, K-, E-, and N-type;  
and 0.08 % of reading for T-type]  
Electromagnetic  
Compatibility  
Susceptibility: ± 2 oC (± 3.6 oF) for 80 MHz to 200 MHz in 1.5 v/m field, for 200 MHz to  
1000 MHz in 3 V/m field.  
Emissions: Commercial limits per EN50081-1  
Maximum  
Differential  
Common Mode  
Voltage  
1 V (Maximum voltage difference between T1 and T2)  
Temperature  
Scale  
ITS-90  
Applicable  
Standards  
NIST-175  
Accuracy is specified for ambient temperatures between +18 oC (+64 oF) and +28 oC (+82 oF) for a period of  
1 year. The above specifications do not include thermocouple error.  
4
 
 
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  
Recommended Model  
Output Voltage: 0-1V  
Accuracy: 0.0125 %  
Resolution: 0.1 µV  
DC Voltage Calibrator  
Fluke 5700A or equivalent  
Fluke 80CK-M  
Fluke P/N 779942  
Fluke P/N 601747  
Omega  
Thermocouple connector  
For K-type thermocouple  
Copper  
Thermocouple connector  
K-type Thermocouple wire  
Dewar Flask/Cap  
Standard  
1- pint, or larger capacity  
Thermos  
Mercury Thermometer  
(either °C or °F)  
0.02 °C Resolution  
0.05 °F Resolution  
Princo Model ASTM56C  
Princo Model ASTM56F  
DB9 Adapter Connector  
IR Adapter  
Fluke P/N 804549  
Fluke P/N 690518  
PC with Microsoft Windows®  
installed  
Performance Tests  
Performance tests are recommended for incoming inspection, periodic maintenance, and  
for checking the thermometer’s specifications. If the thermometer fails any part of the  
performance tests, calibration and/or repair is indicated.  
Before performing these tests:  
1. Allow the thermometer to stabilize to room temperature, +23 oC ± 5 oC (+73 oF ± 9 oF).  
2. Check the batteries and replace them if necessary.  
Display Test  
Turn the thermometer on while pressing the h button. All display segments are  
displayed until the h button is released. Confirm that all the display segments are  
showing as in Figure 1.  
5
 
 
51, 52, 53, 54 Series II  
Service Manual  
51  
53  
52  
54  
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.  
Ice Bath Construction  
To begin the performance test, first construct an ice bath as follows:  
1. Prepare a Dewar Flask by drilling two holes in its cap to accept the Mercury  
thermometer and thermocouple wires, or use a standard laboratory cork.  
2. Fill the Dewar Flask with shaved or crushed ice made from distilled water.  
3. Fill the Dewar Flask with enough distilled water so that the ice turns to slush, but do  
not add enough water to float the ice.  
Note  
As the ice melts, siphon off the excess water and add more ice. Allow  
approximately 5 to 10 minutes for the water to drop back to the freezing  
point.  
6
 
 
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.  
K-Type Thermocouple wire  
K-Type  
Thermocouple  
connector  
Copper wire  
Mercury  
Thermometer  
-
+
-
+
51, 52, 53, or 54  
Series II  
Thermometer  
5700A  
Calibrator  
Ice bath  
+
-
zb04f.eps  
Figure 2. Ice Bath Test Equipment Connections  
Ice Bath Test  
Use the following procedure to test the thermometer. If the thermometer has two inputs,  
this test should be conducted on both thermocouple inputs.  
1. If not already selected, select K-type thermocouple on the thermometer using the  
D, K, N, and Ebuttons.  
2. Connect the equipment as shown in Figure 2. Allow the setup to thermally stabilize at  
least 5 minutes after inserting the thermocouple into the thermometer.  
3. Verify that the ice bath temperature reads 0.0 oC ± 0.06 oC on the Mercury  
thermometer.  
4. Short (or apply 0 mV) to the copper wires at the Calibrator.  
5. Verify the thermometer reads 0.0 oC ± 0.3 oC.  
6. If this test fails, reposition the thermocouple wires and Mercury thermometer to the  
same depth in the ice bath, and repeat steps 3-5. If the test continues to fail, perform  
the calibration procedure, located after this procedure.  
7. Remove the short applied in step 4.  
8. Using Table 3, steps 2-5, obtain an output from the Calibrator equal to the values in  
the “Input Voltage (mV DC)” column, and verify the thermometer reads within the  
limits specified. If any step fails, perform the calibration procedure located later in  
this section.  
9. Disconnect the thermocouple from the input terminals. This completes the ice bath  
test.  
7
 
 
51, 52, 53, 54 Series II  
Service Manual  
Table 3. Performance Test Values (K-Type Thermocouple)  
Input  
Voltage  
Equivalent  
Display Reading limits  
Step  
(mV DC)  
Temperature  
°C  
°F  
1
2
3
4
5
0.0000  
0.9193  
-5.7297  
40.8853  
48.8382  
0.0 °C  
32.0 °F  
-0.3 to 0.3  
31.5 to 32.5  
72.9 to 73.9  
23.0 °C  
-190.0 °C  
990.0 °C  
1200 °C  
73.4 °F  
22.7 to 23.3  
-189.3 to -190.7  
989.2 to 990.8  
1199 to 1201  
-310.0 °F  
1814 °F  
2192 °F  
-308.9 to -311.1  
1813 to 1815  
2190 to 2194  
Verification of IR Communications Port (Fluke 53 and 54)  
This section explains how to verify the operation of the IR Communications Port (IR  
port). Perform the following procedure using a PC and HyperTerminal. The IR port can  
also be verified using Flukeview software.  
To set up a HyperTerminal file, follow these steps:  
1. Connect the IR adapter cable to the DB9 Adapter connector. Connect the other end of  
the DB9 Adapter to a COM port of the PC.  
2. Place the Fluke 53 or 54 in front of the IR adapter.  
3. Open up a HyperTerminal session. Select Start button, Programs, Accessories,  
HyperTerminal.  
4. Open up a New Connection with a name like “Fluke 54 IR Test”.  
5. When the Connect To box appears, select the COM1 or COM2 (the port that the IR  
adapter cable is plugged into).  
6. Select Port Settings: 9600 baud rate, 8 data bits, no parity, 1 stop bit, and no flow  
control.  
7. Under File, select properties. Verify that the correct port is selected. Click on  
Configure. Verify that port settings are correct (the baud rate may need to be  
changed to 9600).  
8. Select the Settings tab then click on ASCII Setup. Check the following boxes:  
Echo typed characters locally  
Append line feeds to incoming line ends  
Wrap lines that exceed terminal width  
To open a HyperTerminal file to test the IR port, use the following procedure:  
1. Under File, select Save As. Use a file name such as “Fluke 54 IR Test” and then  
click on save.  
2. Click on the phone disconnect icon.  
3. Click on open folder or under File select Open. Double click on Fluke 54 IR Test.  
4. Type in "ID" followed by the Enter key (notice the "ID" is capitalized).  
5. The display of the thermometer now shows the thermometer name (Fluke 53-II or  
Fluke 54-II), and the units operating software version (e.g. Fluke 54-II, V1.01).  
8
 
 
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 (non-  
thermocouple) wire and a copper thermocouple connector. Refer to Figure 3 for  
proper equipment connections.  
2. Turn the thermometer on, with a small, blunt probe, press the calibration button  
located on the back and in the center of the thermometer. Refer to Figure 4.  
Copper  
Thermocouple  
connector  
-
+
51, 52, 53, or 54  
Series II  
Thermometer  
Copper  
wire  
5700A  
Calibrator  
+
-
zb06f.eps  
Figure 3. Calibration Connections  
9
 
 
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.  
CAL Abrt ignores calibration changes (turning the thermometer off  
while in CAL will also ignore calibration changes).  
4. Press K or Nto select different menu options.  
5. With CAL A-d selected, press E. The thermometer prompts “80”. Set the  
calibrator to +80.000 mV and allow the output to stabilize.  
Note  
For steps 6 and 8, keep hand and body motion to a minimum while the  
thermometer takes A/D readings.  
6. Press E. Wait while it takes A/D readings.  
7. When the thermometer prompts for “-8”, set the Calibrator to -8.0000 mV. Allow the  
output to stabilize.  
8. Press E on the thermometer and wait while it takes A/D readings. The  
thermometer now shows the measured value in the bottom portion of the display.  
Millivolts appears on the left side and microvolts appears on the right side.  
9. If the measurement is from –7 995.0 to –8 005.0, press E and the meter will  
return to the calibration menu and display CAL rEF. If the measurement is outside –  
7995.0 to –8005.0, press Eonce to return to the calibration menu. Using  
K or N, select CAL A-d and try the A/D calibration procedure a second time  
starting at step 5.  
10. Using K or N, select “CAL donE”, then press E to store the calibration in  
memory.  
10  
 
 
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).  
Note  
It is important that the temperature of the thermocouple and the internal  
temperature of the thermometer (the reference junction) have stabilized.  
To calibrate the reference junction, follow these steps:  
1. Prepare an ice bath (described earlier in this section).  
2. Referring to Figure 2, connect the equipment to T1 using K-type thermocouple wire  
and a K-type thermocouple connector. Allow the setup to thermally stabilize at least  
5 minutes after inserting the thermocouple connector into the thermometer.  
3. Turn the thermometer on and select the thermocouple type using the D, K, N,  
and Ebuttons.  
4. Enter calibration mode (refer to the “A/D Calibration” section, step 2).  
5. Using Kor N, select CAL rEF and press E.  
6. Press Kor Nuntil the upper display matches the known temperature.  
Note  
Once adjusted, do not change units (°C, °F, or K) until the thermometer is  
in measurement mode.  
7. Press the E button.  
8. “CAL donE”appears then press E to store the calibration in memory.  
9. To ignore the calibration changes, use the K or N, and select “CAL Abrt” and  
press E.  
Using the Offset to Adjust for Variation Between Thermocouples  
Use the offset option in the thermometer SETUP mode to adjust the thermometer's  
readings for errors of a specific thermocouple. Use the following procedure:  
1. Plug the thermocouple into the thermometer input then allow the setup to thermally  
stabilize at least 5 minutes.  
2. Place the thermocouple in a known, stable temperature environment (such as an ice  
bath, lag bath, or a dry well calibrator).  
3. Allow the readings to stabilize.  
4. In SETUP, change the offset until the primary display reading matches the bath  
temperature. (See "Changing Setup Options” in the 51/52 Series II Users Manual,  
and the 53/54 Series II Users Manual.)  
11  
 
 
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.  
The pca may be washed with isopropyl alcohol or deionized water and a soft brush. Dry  
the pca with clean dry air at low pressure, then bake it at +50 oC (+122 oF) for 24 hours.  
Changing the Batteries  
WWarning  
Replace the batteries as soon as the low battery indicator (B)  
appears. The possibility of false readings increases when  
the batteries are low. False readings can lead to personal  
injury.  
To avoid electrical shock, disconnect the thermocouple(s)  
before opening the battery door.  
Caution  
Do not attempt to recharge the batteries.  
Do not dispose of the batteries by placing them in fire.  
Follow local laws or regulations when disposing of  
batteries.  
Match the positive (+) and negative (-) polarities of the  
batteries with the markings located on the case.  
To replace the batteries, refer to Figure 5 and use the following procedure:  
1. Turn the thermometer off.  
2. Loosen the battery compartment door screw and remove the battery door.  
3. Replace the three AA batteries. To simplify battery installation, put the new batteries  
into the unit positive end first.  
4. Replace the battery compartment door and tighten the screw.  
12  
 
 
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.  
Caution  
Before proceeding, make sure that you are grounded to  
prevent static discharge, which could damage the  
thermometer.  
Inside the unit there are parts that can become  
contaminated by oils from the skin. These parts should not  
be directly handled. When lifting out the elastomeric  
connectors and the main switch pad, it is recommended that  
tweezers or sterile gloves be used.  
3. Remove the two case bottom screws, located at the LCD-end of the unit and separate  
the bottom case from the top case.  
4. Removing any of the interior components of the unit requires removing the Main  
PCA. To remove the Main PCA, place the top case face down and remove the two  
screws that attach the Main PCA to the top case. Gently lift the Main PCA out of the  
top case. The IR Lens, small Isothermal PCA, backlight, elastomeric connectors, and  
the LCD may all lift out attached to the Main PCA.  
5. If the Isothermal PCA separates from the Main PCA, the Isothermal PCA, IR Lens,  
backlight, elastomeric connectors, and the LCD will still be in the top case. Lift them  
out of the top case after the Main PCA is removed.  
13  
 
 
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.  
Note  
For reassembly, the thermometer top case should be face down, with the  
keypad end of the top case facing the user.  
Reinstalling the LCD Assembly  
Follow these steps to reinstall the LCD assembly:  
1. Install the LCD decal.  
2. When putting the LCD back into the top case, make sure the LCD is correctly  
aligned. The edge of the LCD with the bubble in it should be facing the left side of  
the open, face down top case, and the LCD should be placed into the top case face  
down.  
3. When reinstalling the backlight, the backlight pins should be on the left side of the  
open top case and they should be facing up. Check that the pins are straight. To make  
sure that the backlight is centered, line up the bottom left corner of the backlight with  
the guide that is molded into the top case. The left corner of the backlight should fit  
directly over this guide and the bottom right side of the backlight should also be lined  
up with (but not over) a similar guide on the right side of the open top case.  
4. Install the two LCD elastomeric connectors.  
Rebuilding the Main PCA  
When reinstalling the Main PCA, make sure that the Isothermal PCA and the IR Lens are  
attached to each other first. To do this, follow these directions:  
1. Turn the Main PCA over so that the components are face down.  
2. Attach the Isothermal PCA to the Main PCA by inserting the pins into the matching  
holes on the Main PCA.  
Note  
When putting the Isothermal PCA back onto the Main PCA, do not push the  
Isothermal PCA all the way down into the contact holes of the Main PCA. If  
the Isothermal PCA is kept slightly loose, it makes installation of the IR  
Lens easier.  
3. Reinstall the IR Lens by taking the Main PCA (with the Isothermal PCA loosely  
attached), and with the component side facing down; slide the IR Lens in between the  
main board and the Isothermal PCA.  
4. Line up the tab on the Isothermal PCA and the notch in the IR Lens and push the two  
together. The contacts of the IR Lens should slide under the Isothermal PCA and they  
should be making contact with pads on the underside of the Isothermal PCA.  
14  
 
 
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. Align the Main PCA holes with the backlight posts.  
5. Gently push the Main PCA down into the top case, making sure that the IR Lens goes  
into the groove on the LCD-end of the top case. If it does not fit together easily,  
check to make sure that everything is properly lined up and try again.  
6. Reinsert and tighten the two pca screws.  
To complete the thermometer reassembly, screw the bottom case to the top case, reinstall  
the batteries and screw the battery compartment shut.  
Replaceable Parts  
Refer to Table 4 for all replacement part numbers and Figure 6 for part locations. Unless  
specified in the “Model Number” column, all parts are for all units. To order replaceable  
parts, see the “Service Centers” section of this manual.  
Table 4. Replaceable Parts  
Item  
Fluke Part  
Model  
Number  
Qty. Number  
Description  
Number  
1
2
3
4
376756  
803582  
BATTERY, PRIMARY, 1.5V, 0-150MA, AA ALKALINE  
SCREW , PH, P, CAPT, STL, 4-40, .25  
BATTERY DOOR:  
All  
All  
3
4
1
1
642931  
669838  
SCREW, PH, P, AM THD FORM, STL, 4-14, .312  
DOOR, BATTERY  
All  
All  
5
1
669812  
669804  
669801  
669796  
CASE, TOP  
CASE, TOP  
CASE, TOP  
CASE, TOP  
51  
52  
53  
54  
6
7
1
2
1
1541901  
804713  
ISOTHERMAL PCA (TESTED)  
All  
All  
All  
CONNECTOR, ELASTOMERIC, LCD TO PWB, 2.210 L  
BOTTOM CASE ASSEMBLY  
8A-F  
1541895  
Bottom Case Assembly contains:  
8A  
8B  
8C  
8D  
8E  
8F  
2
1
1
1
1
1
666435  
674744  
674770  
669819  
658689  
675009  
BATTERY CONTACT, DUAL  
BATTERY CONTACT (POS)  
BATTERY CONTACT (NEG)  
CASE, BOTTOM  
All  
All  
All  
All  
All  
All  
KEYPAD, CALIBRATION  
SHIELD  
15  
 
 
51, 52, 53, 54 Series II  
Service Manual  
Table 4. Replaceable Parts (cont.)  
Description  
Item  
Number  
Fluke Part  
Number  
Model  
Number  
Qty.  
9A-B  
1
1541912  
1543462  
51/53 SERIES II IR LENS KIT  
52/54 SERIES II IR LENS KIT  
51, 53  
52, 54  
1
IR Lens Kit contains:  
9A  
9B  
2
4
__  
__  
SPRING, ISOTHERMAL  
51, 53  
52, 54  
1
1
1
1
IR LENS  
IR LENS  
51, 53  
52, 54  
All  
10  
11  
675017  
WINDOW, PROTECTOR  
675030  
675025  
675022  
675014  
LCD DECAL  
LCD DECAL  
LCD DECAL  
LCD DECAL  
51  
52  
53  
54  
12  
13  
14  
15  
1
1
2
1
674747  
1272438  
643830  
BACKLIGHT  
All  
All  
All  
HOLSTER & FLEX STAND ASSEMBLY  
SCREW, PH, P, METRIC PT, STL, K35, 14MM  
669793  
669788  
669785  
669777  
KEYPAD  
KEYPAD  
KEYPAD  
KEYPAD  
51  
52  
53  
54  
16  
1
1
1
804705  
800836  
1276106  
CONNECTOR, ELASTOMERIC, SWITCH TO PWB, 1.200 L  
LCD, MULTIPLEXED  
All  
All  
All  
17  
Not shown  
CD ROM, CD ROM FLUKE 50 SERIES II  
CD ROM contains:  
51/52 Series II Users Manual (16 Languages)  
53/54 Series II Users Manual (16 Languages)  
Not shown  
Not shown  
1
1276114  
773135  
FLUKE 51-54 SERIES II PRODUCT OVERVIEW  
All  
1
2
THERMOCOUPLE ASSY, T/C ASSY, K-TYPE, BEADED, MOLDED-  
PLUG  
51, 53  
52, 54  
16  
 
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. Exploded View (Model 54 is Shown)  
17  
 
 
51, 52, 53, 54 Series II  
Service Manual  
18  
 
Index  
—A—  
—I—  
assembly, 13  
ice bath  
construction, 6  
equipment connections, 7  
—B—  
batteries  
changing, 12  
—L—  
LCD  
reinstalling, 14  
—C—  
calibration, 9  
—M—  
A/D, 9  
A/D connections, 9  
button access, 10  
CAL Abrt, 10  
Main PCA  
rebuilding, 14  
reinstalling, 15  
maintenance  
CAL A-d, 10  
CAL donE, 10  
CAL rEF, 10  
offset, 9  
batteries, changing, 12  
cleaning, 12  
reference junction, 11  
variations between thermocouples, 11  
caution, 12, 13  
CD ROM, 1  
—P—  
parts  
diagram, 17  
performance tests, 5  
display test, 5  
—D—  
disassembly, 13  
display  
IR communications port verification, 8  
keypad test, 6  
segments, 6  
test values, k-type thermocouple, 8  
wide range, 6  
precautions, 2  
—E—  
electrical symbols, 2  
—R—  
—H—  
reassembly, 14  
HyperTerminal, 8  
1
 
51, 52, 53, 54 Series II  
Service Manual  
performance testing and calibration, 5  
—S—  
safety, 2  
—U—  
cautions and warnings, 3  
service centers  
Users Manual  
phone numbers, world wide web address, 2  
specifications  
51, 52 Series II, 1  
53, 54 Series II, 1  
environmental, 4  
general, 4  
—W—  
warnings, 1, 12  
—T—  
test equipment  
2
 

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