manual de servicio balanza de humedad MB45 ohaus

Ohaus Corporation19A Chapin RoadP.O. Box 2033,Pine Brook, NJ 07058-2033

Ohaus Corporation 19A Chapin Road, P.O. Box 2033, Pine Brook, NJ 07058-2033 (973) 377-9000

MB45 MOISTURE ANALYZER

SERVICE MANUAL

The information contained in this manual is believed to be accurate at the time ofpublication, but Ohaus Corporation assumes no liability arising from the use or misuseof this material. Reproduction of this material is strictly prohibited.

Material in this manual is subject to change.

© Copyright 2006 Ohaus Corporation, all rights reserved.® Registered trademark of Ohaus Corporation.

SERVICE MANUAL

Ohaus Corporation19A Chapin RoadP.O. Box 2033Pine Brook, NJ 07932-0900

MB45 MOISTURE ANALYZER

On/OffTest Menu

DisplaySetup

Enter

PrintTARE

START/STOP

MB45

i

TABLE OF CONTENTS

CHAPTER 1 INTRODUCTION

1.1 Introduction .......................................................................................... 1-11.2 Service Facilities .................................................................................... 1-11.3 Tools and Test Equipment Required ...................................................... 1-2

1.3.1 Special Tools .................................................................................. 1-21.3.2 Tools and Supplies ........................................................................ 1-2

1.4 Test Mass Required ................................................................................ 1-21.5 Specifications ......................................................................................... 1-2

1.5.1 Admissable Ambient Conditions ..................................................... 1-2

CHAPTER 2 OPERATION2.1 Menu Structure .................................................................................. 2-12.2 Control Switch Functions................................................................... 2-22.3 Adjusting the Display Contrast and Brightness ................................. 2-3

CHAPTER 3 TROUBLESHOOTING3.1 Troubleshooting ...................................................................................... 3-13.2 Troubleshooting Guide ........................................................................... 3-1

3.2.1 Diagnosis ........................................................................................ 3-1

CHAPTER 4 MAINTENANCE PROCEDURES4.1 Preventive Maintenance ......................................................................... 4-1

4.1.1 Visual Inspection ............................................................................ 4-14.1.2 Preventive Maintenance Checklist.................................................. 4-1

4.2 Testing .......................................................................................... 4-24.2.1 Operational Test ............................................................................. 4-2

4.2.1.1 Display Test ...................................................................... 4-24.2.2 Weight Calibration .......................................................................... 4-34.2.3 Temperature Calibration ................................................................. 4-44.2.4 Performance Tests .......................................................................... 4-5

4.2.4.1 Precision Test ................................................................... 4-54.2.4.2 Off-Center Load Test ......................................................... 4-64.2.4.3 Centered Load Test ........................................................... 4-64.2.4.4 Visual Inspection ............................................................... 4-6

4.3 Repairing the Moisture Analyzer ............................................................. 4-64.3.1 Repairing the Drying Unit ............................................................... 4-7

4.3.1.1 Dismantling the Heating Module ....................................... 4-74.3.2 Replacing the Protective Glass and Reflector................................. 4-8

4.3.2.1 Replacing the Protective Glass and Reflector ................... 4-84.3.2.2 Installing Protective Glass and Reflector ........................... 4-8

4.3.3 Replacing the Halogen Lamp ......................................................... 4-84.3.3.1 Dismantle Halogen Lamp .................................................. 4-84.3.3.2 Installing the Halogen Lamp .............................................. 4-9

4.3.4 Replacing the Temperature Controller ............................................ 4-94.3.5 Replacing the Temperature Sensor .............................................. 4-10

Page

ii

4.3.6 Installing the Heating Module ....................................................... 4-104.3.7 Removing Housing Top ................................................................ 4-114.3.8 Removing the Membrane Keypad ................................................ 4-134.3.9 Installing the Membrane Keypad .................................................. 4-134.3.10 Replacing the Display................................................................... 4-144.3.11 Replacing the Fan ........................................................................ 4-144.3.12 Replacing the CPU Board ............................................................ 4-154.3.13 Replacing the Power Supply Board .............................................. 4-164.3.14 Replacing the Weighing Cell ........................................................ 4-174.3.15 Replacing the Housing Base ........................................................ 4-184.3.16 Installing the Housing Top.............................................................. 4-19

4.4 Resetting the Thermal Overload Device ................................................ 4-204.5 Final Work Steps ................................................................................... 4-21

CHAPTER 5 DRAWINGS AND PARTS LISTS5.1 Drawings and Parts Lists ........................................................................ 5-1

5.1.1 Top Housing ................................................................................... 5-25.1.2 Bottom Housing .............................................................................. 5-45.1.3 Dryer Unit ........................................................................................5-7

APPENDIX A SOFTWARE SERVICE TOOL INSTRUCTIONSA.1 Software Service Tool Instructions ...................................................... A-1A.2 Requirements ...................................................................................... A-1A.3 Instructions and Notes ......................................................................... A-1A.4 Error Messages ................................................................................... A-4

CHAPTER 4 MAINTENANCE PROCEDURES (Cont.)

TABLE OF CONTENTS (Cont.)

iii

TABLE OF CONTENTS (Cont.)

LIST OF TABLES

TABLE NO. TITLE PAGE NO.

1-1 Specifications ................................................................................. 1-22-1 Menu structure ................................................................................ 2-13-1 Diagnostic Guide ............................................................................ 3-24-1 Types of Performance Tests ........................................................... 4-55-1 Spare Parts List Top Housing ......................................................... 5-35-2 Spare Parts List Bottom Housing .................................................... 5-55-3 Spare Parts List Dryer Unit ............................................................. 5-7

LIST OF ILLUSTRATIONS

FIGURE NO. TITLE PAGE NO.

4-1 Access for Cleaning MB45 Moisture Analyzer ................................ 4-14-2 Display Test .................................................................................... 4-24-3 Dismantling the Heating Module ..................................................... 4-74-4 Removing the Heating Module ....................................................... 4-74-5 Replacing Protective Glass ............................................................ 4-84-6 Replacing Halogen Lamp ............................................................... 4-84-7 Installing the Halogen lamp ............................................................ 4-94-8 Replacing Temperature Controller.................................................. 4-94-9 Replacing Temperature Sensor .................................................... 4-104-10 Installing Heat module .................................................................. 4-104-11 Replacing Cover ........................................................................... 4-114-12 Remove Housing .......................................................................... 4-114-13 Remove Cable from Display ......................................................... 4-124-14 Remove Connectors ..................................................................... 4-124-15 Remove Membrane Keypad ......................................................... 4-134-16 Install Membrane Keypad ............................................................. 4-134-17 Replacing Display ........................................................................ 4-144-18 Replacing Fan .............................................................................. 4-144-19 Replacing CPU Board .................................................................. 4-154-20 Replacing Power Supply Board.................................................... 4-164-21 Replacing Weighing Cell .............................................................. 4-174-22 Replace Housing Base ................................................................. 4-184-23 Install Housing Top ....................................................................... 4-194-24 Plug in Cables .............................................................................. 4-194-25 Housing Top Reassembly .............................................................. 4-204-26 Resetting the Thermal Overload Device ........................................ 4-20

5-1 Top housing .................................................................................... 5-25-2 Bottom Housing .............................................................................. 5-45-3 Dryer Unit ........................................................................................ 5-6

iv

1-1


DO NOT SERVICE the Moisture Analyzer:

• Next to open windows or doors causing drafts or rapid temperature changes.

• Near air conditioning or heat vents.

• Near vibrating, rotating or reciprocating equipment.

• Near magnetic fields or equipment that generates magnetic fields.

• On an unlevel work surface.

• Allow sufficient space around the instrument for ease of operation and keep away from radiating heat sources.

1.1 INTRODUCTIONThis service manual contains the information needed to perform routine maintenance and service on the Ohaus MB45Moisture Analyzer.

The contents of this manual is contained in five chapters.

Chapter 1 Introduction - Contains information regarding service facilities, tools and test equipment, measuringmasses, and specifications.

Chapter 2 Operation - Contains information on the control functions of the Moisture Analyzer.

Chapter 3 Troubleshooting - Contains a diagnosis/diagnostics chart and error code table.

Chapter 4 Maintenance Procedures - Contains preventive maintenance procedures, performance tests andadjustments, disassembly/replacement procedures, and calibration procedures.

Chapter 5 Drawings and Parts Lists - Contains exploded views of all assemblies identifying serviceablecomponents with parts lists.

Before servicing the Moisture Analyzer, you should be familiar with the Instruction Manual which is packed with every unit.

1.2 SERVICE FACILITIESTo service the Ohaus MB45 Moisture Analyzer, the service area should meet the following requirements:

On/OffTest Menu

DisplaySetup

Enter

PrintTARE

START/STOP

MB45

On/OffTest Menu

DisplaySetup

Enter

PrintTARE

START/STOP

MB45

On/OffTest Menu

DisplaySetup

Enter

PrintTARE

START/STOP

MB45

1-2


1.3 TOOLS AND TEST EQUIPMENT REQUIREDThis section contains information on tools and supplies required to properly service the MB45 Moisture Analyzer. These itemsare listed as follows:

1.3.1 Special ToolsNone required.

1.3.2 Tools and Supplies

1.Digital Voltmeter (DVM) - Input impedance of at least 10 megohms in the 1 Volt dc position.

2.Standard electronics tool kit

3.Soldering iron (50 watt) and solder (rosin core solder, not acid core).

4.Solder remover.

5.Ohaus Temperture Calibration Kit P/N 11113857

6.Soft, lint-free cleaning cloth

7.Anti-static bags for PCBs

8.Anti-static wrist strap and mat

1.4 TEST MASS REQUIREDIt is recommended that a ASTM Class 1 Tolerance mass be used. The mass required is 20 grams.

Capacity 45gReadability 0.001g, .01%Heat Source Halogen bulb - 120 V or 240 VCalibration External calibration mass-20gDimensions (DxWxH) (in/cm) 14 x 7.5 x 7/ 35.5 x 19 x 17.8Operating Temperature Range 10°C to 40°CPower Requirements 100V ac -127V ac or 230V ac - 240V ac, 50/60HzWeight (lb/kg) 9.8 / 4.5Shipping Weight (lb/kg) 14.1 / 6.4

1.5 SPECIFICATIONSComplete specificatons for the MB45 Moisture Analyzer are listed in Table 1-1. When an MB45 has been serviced, it mustmeet the specifications listed in Table 1-1. Before servicing the Moisture Analyzer, determine what specifications are notmet.

TABLE 1-1. SPECIFICATIONS

1.5.1 Admissible Ambient ConditionsUse only in closed rooms

Temperature range: 5 ºC to 40 ºCAtmospheric humidity: 80% rh @ to 30 ºCVoltage fluctuations: –15% +10%Installation category: IIPollution degree: 2Power load: Max. 450 W during drying processCurrent consumption: 4 A or 2 A, according to the heating elementPower supply voltage: 100 V – 120 V or 200 V – 240 V, 50/60 Hz

(the voltage is given by the heating element)Power line fuse: 1 piece, 5 x 20 mm, T6,3 H 250 V

2-1

CHAPTER 2 OPERATION

2.1 MENU STRUCTUREThis chapter contains menu structure, control swich operation and display adjustments. For complete operation, refer tothe Instruction manual supplied with the unit. The menu structure is illustrated in the table below.

TEST MENUTest Library

Edit Test

Test ParametersTest ID:

Profile:

StandardFast

Ramp

StepDry Temp:

Switch Off:

Timed- Switch OffManual-Use Start/Stop

AFREE - Wt loss/time

A90 - <1MG in 90 secondsA60 - <1MG in 60 seconds

A30 - <1MG in 30 seconds

Result:% Moisture

Custom UnitsGrams

% Regain

% SolidsCustom

Factor, Exponent, LSD

Target Wt:Print Int:

Off, 1, 3, 5, 10, 30 Sec

1, 2, 5 Min.Save Test:

SetupLockout

Weight CalibrationTemperature Calibration

Language

English, Deutsch, Espaniol,Francais, Italiano

Beeper

Low, High, OffTime-Date

Format

MM/DD/YR, DD/MM/YRSet Date

Time format

12HR, 24HRSet Time

AM, PM

RS232Baud Rate

1200, 2400, 4800, 9600,19,200

Parity

Odd, Even, NoneData Bits

7, 8

Stop Bits1, 2

Handshake

None, XON-XOFF, RTS-CTSPrint

Print On/Off

GLP On/OffDisplay

ContrastBrightness

Factory Reset

01

Load TestEdit Test

Delete Test

02Load Test

Edit Test

Delete Test•

•

••

50

Load TestEdit Test

Delete Test

SETUP

TABLE 2-1. MENU STRUCTURE

2-2

CHAPTER 2 OPERATION

2.2 CONTROL SWITCH FUNCTIONS

On/OffTest Menu

DisplaySetup

Enter

PrintTARE

START/STOP

MB45

4

2

5

10

3

12

7

9

8

6

11

No. Designation Function

1 Turns ON/OFF display and fan. ON returns with last screen. (All modes)

2 Test Menu button When pressed, selects Test Library screen.

3 Display button When pressed, will return to the current test or cycles through several displayscreens (run mode).

4 Setup button When pressed, brings up analyzer setup menu. 5 5 Start/Stop button When pressed, either starts or stops drying process.

6 button When pressed, travels up through menu options and selects alphanumeric

characters.

7 button When pressed, travels to the left through displays.

8 button When pressed, travels to the right through displays.

9 button When pressed, travels down through menu options and selects alphanumeric

characters.

110 Enter/Print button When pressed, accepts selection/input (select mode) or sends print commandduring a test (run mode).

11 Tare button When pressed, performs a tare function. Pressing during a test has no effect.

12 Leveling feet Used to level the Moisture Analyzer.

1

On/Off

Test Menu

Display

Setup Enter Print

TARESTART/STOP

0%��

11

2-3

CHAPTER 2 OPERATION

2.3 ADJUSTING THE DISPLAY CONTRAST AND BRIGHTNESSEnter the ANALYZER SETUP menu, this menu permits adjusting the contrast and brightness levels on the display screen.

To change the levels, proceed as follows:

ANALYZER SETUP Press the Setup button. Using the down arrow button, scroll to DISPLAY. Press

the Enter button.

DISPLAY ADJUST Adjusting contrast

Using the up/down arrow buttons, adjust the screen contrast to the desired level.

The numeric value (0 to 100) is for reference only. Press the right arrow button

to advance to BRIGHT. Default = 40.

LANGUAGEBEEPERTIME-DATERS-232PRINTDISPLAY

CONTRAST: 60

BRIGHT: 10

EXIT WITHOUT SAVING

DISPLAY ADJUST Adjusting brightness

Using the up/down arrow buttons, adjust the screen brightness to the desired

level. The numeric value (0 to 10) is for reference only. Press the Enter button.

Default = 10.

CONTRAST: 60

BRIGHT: 10

EXIT WITHOUT SAVING

Exit without saving

If you do not wish to save settings, Use the right arrow button and scroll to EXIT

WITHOUT SAVING and press the Enter button. The display returns to

ANALYZER SETUP.

DISPLAY ADJUSTCONTRAST: 60

BRIGHT: 10

EXIT WITHOUT SAVING

2-4

CHAPTER 2 OPERATION

3-1

CHAPTER 3 TROUBLESHOOTING

3.1 TROUBLESHOOTINGThis section of the manual specifies problem areas of the MB45 Moisture Analyzer which can occur. Information is containedto isolate specific problems using the Troubleshooting Guide. Make certain that the work area is clean and use care whenhandling components of the Analyzer.

3.2 TROUBLESHOOTING GUIDEA Troubleshooting Guide is designed to help you locate the problem area quickly and easily. First locate the problem thatyou are observing. The probable causes are listed with the most common cause first. Before attempting to repair theAnalyzer, read all chapters of this manual to familiarize yourself with the components and operation. Do not attempt repairsunless you fully understand the operation of the Analyzer.

3.2.1 Diagnosis

1.Isolate and identify the symptom.

2.Review the probable causes in the order that they appear.

3.See the appropriate section of the manual to correct the malfunction.

4.Repair or replace the defective section of the Moisture Analyzer.

In the event that erratic or fluctuating weight readings are observed, it is necessary to isolate the problem to either themechanical area or the electronic area of the Moisture Analyzer.

If a problem arises that is not covered in this manual, contact:

Ohaus Corporation19A Chapin RoadP.O. Box 2033Pine Brook, NJ 07058-2033 USATel: 973-377-9000Fax: 973-944-7177

In the United States call toll free, 800-526-0659 between 8:00 a.m. and 6:00 p.m. EST.

NOTE:If more than one symptom is observed, it is necessary toapproach one area at a time, and also remember, that thesymptoms may be interrelated.

3-2

CHAPTER 3 TROUBLESHOOTING

PROBABLE CAUSE(S)

Power cord not plugged in or no powersupply voltage.

Defective main fuse.

Defective power supply fuse.

Cable connections inside instrument notplugged in or defective.

Defective CPU board.

Defective power supply fuse.

Defective power supply board.

Defective keypad wiring.

Keypad not plugged in

Defective keypad wiring

Defective display.

Thermal overload device has tripped.

Defective temperature controller.

Defective halogen lamp.

Temperature sensor not plugged in ordefective.

Defective power supply board.

Defective CPU board.

Incorrect Halogen bulb

Defective temperature sensor.Defective power supply board.Defective CPU board.

The air current which cools the weighingcell is blocked.

SYMPTOM

Moisture analyzer cannot be switchedon.

Moisture analyzer cannot be switchedon green LED on power supply boarddoes not light up.

Moisture analyzer cannot be switchedon. Green LED on power supplyboard lights up.

Moisture analyzer cannot be switchedon green LED on power supply boarddoes not light up.

Some buttons do not respond.

Keypad does not function.

Portions of the display do not light up.

Halogen lamp does not switch onafter "Start".

Halogen lamp switches off before endof test.

Temperature rises above 205 de-grees C.

Unstable weight indication.

REMEDY

Check

The power supply is designed for100...240 VAC, but the drying unit onlyfor 110 or 230VAC. Check whether thecorrect drying unit is installed. Checkthe fuses on the back of the instru-ment and the power supply board.

Plug in or replace cable.

Replace CPU board.

Replace power supply fuse on powersupply board.Replace power supply board.

Replace membrane keypad.

Check keypad.

Replace membrane keypad.

Replace display.

Reset thermal overload device, seeparagraph 4.4.

Replace if resistance after resetting is> 1 Ohm.Replace if resistance > 20 Ohms(check whether 100 or 230 VAC).

Plug in or replace sensor.

Replace power supply board.

Replace CPU board.

Check voltage rating on bulb.

Replace temperature sensor.Replace power supply board.Replace CPU board.

Clean the ventilation grill.

TABLE 3-1. DIAGNOSTIC GUIDE

3.2 TROUBLESHOOTING GUIDE (Cont.)

4-1

CHAPTER 4 MAINTENANCE PROCEDURES

4.1 PREVENTIVE MAINTENANCEOhaus MB45 Moisture Analyzers are precision instruments and should be carefully handled, stored in a clean dry area whichis dust free, and cleaned periodically. It is recommended that when a Analyzer has had chemicals or liquids spilled on it,the Analyzer should be cleaned as soon as possible. Use warm water on a damp cloth to clean all exterior surfaces. Donot leave a mass on the sample pan when the Analyzer is not in use.

When moving the unit from a storage area which is at a different temperature than the area where it is to be operated, allowsufficient time for the mechanism to temperature stabilize. This time can vary quite a bit depending upon the temperaturedifferences. Allow one (1) hour for each 5 degrees Fahrenheit temperature change before using the Moisture Analyzer. Also,after turning the Analyzer ON, allow five minutes after temperature stabilization for the internal electronics to stabilize.

4.1.1 Visual InspectionWhen a Moisture Analyzer is first received for repairs, the unit should be checked visually for completeness.— Check on completeness in accordance with standard equipment.— Check on the condition of the following parts:

• Housing

• Keypad and display

• Draft shield with heat shield, pan handler and pan support

• Dryer unit with protective glass, Halogen radiator, reflector

• Fan grill (rear)

• Leveling feet and level

• Rating plate

4.1.2 Preventive Maintenance ChecklistOn a regular basis, the MB45 Moisture Analyzer should beinspected and checked as follows:

1.Remove power from the MB45.

2.Remove the Pan Support, Draftshield andHeatshield and inspect the interior and exterior ofthe Moisture Analyzer.

3.Clean the outside of the Moisture Analyzer usinga damp cloth with water or a mild householddetergent.

4. Remove any debris which may have accumulatedunder the pan or shields.

5.Inspect the protec-tive glass shieldand clean any spat-tered materialwhich may haveaccumulated onthe glass.

6.Inspect fan open-ing for excessivedust.

Figure 4-1. Access for Cleaning MB45 MoistureAnalyzer.

Pan Support

Draft Shield

Heat Shield

Glass Shield

4-2


CAUTION

DO NOT USE CHEMICAL CLEANERS OR SOLVENTS OF ANYTYPE. SOME CLEANERS ARE ABRASIVE AND MAY AFFECT THEFINISH OF THE ANALYZER.

7.Check the Power Cord for broken or damaged insulation.

8.Make a visual inspection for faulty connectors, wiring, and loose hardware.

4.1.2 Preventive Maintenance Checklist (Cont.)

4.2 TESTINGBefore servicing the MB45 Moisture Analyzer, an operational test and various performance tests should be made to ascertainwhether or not the unit meets specifications. Turn the Moisture Analyzer on and allow it warm up for at least one hour beforeperforming these tests. Make sure the test area is free from drafts and the surface that the Moisture Analyzer rests on islevel and vibration free. It is recommended that a ASTM Class 1 Tolerance mass be used for the performance tests andadjustments.

4.2.1 Operational Test1.Locate a suitable power source for the Moisture Analyzer. Check the voltage rating of the Moisture Analyzer.

2.Plug the Power Cord into a suitable power source.

NOTE: If possible, record original customer settings so that after repairs, the Moisture Analyzer can be returned ina satisfactory operational mode.

4.2.1.1 Display Test

1.Turn the Moisture Analyzer on, a MB45 Moisture Analyzer display with the Ohaus logo should appear followedby the software revision currently installed in the Moisture analyzer. After this display, a standard displayappears. This is a display test. Figure 4-2 is a full display test. The software revision will only appear after pluggingin the analyzer for the first time. Subsequent power on using the On/Off button will not display the software revision.

2.Press the TARE button. The display should indicate a zero weight.

Sr 1.06b

CLEARPANPRESSTARE

TEST ID: -DEFAULT-TEMP/TIME: 100C / 10:00TARG. WGT: 1 GRAMS

0.000* GRAMS

®

Figure 4-2. Display Test.

4-3


4.2.2 Weight Calibration

The Moisture Analyzer can be span calibrated with an external mass of 20 grams. Calibration of the Moisture Analyzer

balance is not absolutely necessary for a correct moisture determination as the measurement is relative. The balance

determines the weight of the sample before and after drying and the moisture is calculated on the basis of the ratio between

wet and dry weights.

Nevertheless, you should calibrate the built-in balance under the following conditions:

— If this is stipulated by your quality assurance system (GLP, GMP, ISO 9001).

— If you suspect the analyzer has been abused.

— Before and after all repairs.

To calibrate the Analyzer, proceed as follows:

Press the Setup button. Using the arrow buttons, scroll to WEIGHT CAL. Press

the Enter button.

ANALYZER SETUPLOCK OUTWEIGHT CALTEMP CALLANGUAGEBEEPERTIME-DATE

The display screen highlights the action you should take.

Clear the pan handler, a sample pan should be in place, close the cover on the

Moisture Analyzer.

Press the Display button to return to display. To abort, press START/STOP

button.

WEIGHT CAL

PLACE 20G MASS

TO ABORTPRESS STRT/STP KEY

Place the required weight on the sample pan, close the cover.

Follow the instructions on the display. The display indicates if the calibration was

successful.

4-4


4.2.3 Temperature CalibrationYou must have an Ohaus Temperature Calibration Kit, (Part Number 11113857) to perform this procedure. If the Moisture

Analyzer has been recently used, allow at least 30 minutes before performing calibration.

Press the Setup button. Using the arrow buttons, scroll to TEMP CAL.

Press the Enter button. You are now prompted to remove the pan handler and

pan support. Replace the pan handler and place a temperature calibration unit

on the pan handler.

NOTE: The unit will not calibrate with the pan support in place.

ANALYZER SETUPLOCK OUTWEIGHT CALTEMP CALLANGUAGEBEEPERTIME-DATE

NOTE: The Temperature Calibration Kit is available as optional equipment.

TEMP CAL

Press the Enter button to initiate the temperature calibration process. Follow the

screen prompts throughout the process.

TEMP CAL 100C

The dryer unit is heated to a temperature of 100°C. You can observe the progress

on the display as the dryer temperature and count down period are displayed.

After 15 minutes, read the thermometer through the inspection window on the

cover and enter this temperature. Using the up/down arrow buttons, adjust the

display reading to agree with the thermometer. Use the left/right arrow buttons

to highlight ACCEPT NEW CAL, then press the Enter button. You have 10

minutes to make this adjustment, otherwise the calibration is terminated.

TEMP CAL 160CThis is a two point adjustment (100°C and 160°C). The dryer unit now heats to

the second temperature (160°C). Adjustment of the temperature is defined by

two points. Proceed exactly as you did for the first temperature. After you have

set the display to agree with the thermometer, highlight ACCEPT NEW CAL,

then press the Enter button. The display returns to ANALYZER SETUP.

WARNING: Be careful when removing the temperature calibration unit from the

dryer unit as it can be very hot. Allow it to cool down by opening the cover before

removing.

Remove the calibration unit. Replace the pan support and the pan handler in their

proper positions.

CURRENT TEMP: --- CTM TO CAL POINT: 15:00 MIN

ADJ CAL READING: 100 C

CURRENT TEMP: 100 CTM TO CAL POINT: 15:00 MIN

ADJ TO CAL READING: 160 C

REMOVE PAN HANDLER AND PAN SUPPORT

ABORT CALIBRATION

ACCEPTS NEW CALABORT CALIBRATION

ACCEPTS NEW CALABORT CALIBRATION

4-5


4.2.4 Performance TestsAccurate performance of the MB45 Moisture Analyzer is determined by a series of three performance tests. Precision,Off Center Load and Centered Load. The displayed readings are compared with the tolerances listed in Table 4-1. Tolerancevalues are expressed in grams. Before starting the performance tests, level the Moisture Analyzer.

TABLE 4-1. TYPES OF PERFORMANCE TESTS

PERFORMANCE TEST TOLERANCE

Precision (Standard Deviation) 0.0015g

Off Center Load +0.004g

Centered Load +0.004g

The following performance tests are used to evaluate the Moisture Analyzer operation before and after repairs. Each MoistureAnalyzer tested must meet the requirements specified in each test as well as the specifications listed in Table 1-1. Beforeproceeding with the following tests, all the procedures starting with paragraph 4.2 must have been accomplished on theMoisture Analyzer first. Tolerance values are expressed in counts. A Moisture Analyzer which passes each of these threetests meets the manufacturing specifications.

4.2.4.1 Precision TestPrecision is a word used in balance specifications meaning the Standard Deviation of a set of similar weight readings. Todetermine whether an Analyzer meets the calculated Standard Deviation value in the Specification Table 1-1, perform thefollowing test:

Test1.Tare the Analyzer. The reading on the display should be 0.000g.

2.Place a 20g mass on the center of the sample pan. Observe and record the reading when the stable indicatorcome on.

3.Remove the mass. Reading should return to 0g +0.002g when the stable indicator is on.

4.Repeat this test for ten readings. If the standard deviation of the readings is less than 0.0015g, the MoistureAnalyzer passes the Precision Test.

CAUTION: Remove the mass from the pan after testing.

AdjustmentIf the deviation for any set of readings (using the same mass placed on the center of the pan) is greater than 0.0015g, theMoisture Analyzer does not meet the Precision Test specification. Inspect and correct the following areas:

1.Check for mechanical obstructions. Any foreign object touching any part of the moving pan linkage assemblywill cause a Moisture Analyzer to fail the Precision Test. Inspect and correct as necessary.

2.An error in the Off-Center Load Test can affect the results of the Precision Test. Inspect and correct if necessary.See Off-Center Load Test.

3.Foreign material or debris located in the balance between the pan and the base will cause the Moisture Analyzerto fail the test.

4.Environmental influences such as vibrations, drafts or a non-level surface can cause failures.

4-6


4.2.4.2 Off-Center Load TestThe Off-Center Load Test is used to determine whether displayed weight values will be affected by moving the sample todifferent areas of the sample pan.

(NOTE: Due to the use of relative weighing in moisture analysis, off center load performance is not critical.)

Test1.Place a sample pan on the pan handler.

2.Place 1/2 of the Moisture Analyzer capacity (20 gramms) in the center of the sample pan.

3.Press the TARE button to return the reading to zero.

4.Move the mass halfway (between the center and the edge) to the front of the sample pan. Note any differencesin the displayed weight reading.

5.Repeat this test for the back, left, and right positions.

6.Maximum allowable change in displayed weight readings is +0.004g for each of the four positions. If this readingis exceeded, it usually indicates a defective Weighing Cell.

4.2.4.3 Centered Load TestThis test is used to determine the linearity of the unit throughout its operating range.

NOTES:1. Due to the use of relative weighing and limited use of the weighing range in moisture analysis, linearity

performance is not critical.

2. The Moisture Analyzer must pass the Off-Center Load Test and Precision Test before the Centered LoadTest may be performed.

Test1.Place a 20g mass on the center of the sample pan and note the reading.

2.If the displayed weight is greater than 0.002g higher or lower than the value of the applied mass, and recalibratethe Moisture Analyzer. The Moisture Analyzer should now be calibrated in grams.

3.After completing the above adjustments, check the linearity at 10g and 20g. The displayed weight readings shouldbe equal to the applied mass. Tolerance is +0.004g for each of the respective weight readings. If the displayedweight values are in excess of tolerance count, the Weighing Cell must be replaced.

4.3 REPAIRING THE MOISTURE ANALYZER

Disconnect from power supply and allow heating module to cool !

Important: Electrostatic protection when servicing !

Electrostatic damage is difficult to detect, because the faults it causes are not clear cut. MOS switching transistors withelectrostatic damage have substantially higher, thermically unstable leakage currents. As a result, the Moisture Analyzerbalance drifts more and the display can fluctuate similar to when there is a draft.

To avoid electrostatic damage during production, conducting floors, controlled air humidity, and EMC mats are used. Whenservicing is carried out it is therefore also advisable – as soon as the instrument is opened – to neutralize electrostaticcharges.

4-7


4.3.1 Repairing the Drying Unit

4.3.1.1 Dismantling the Heating Module

1. Swivel drying unit upward.

2. Unscrew 4 screws (a).

3. Pull cover off toward back.

Figure 4-3. Dismantling the Heating Module.

4. Unscrew 2 screws (b).

5. Lift heating module out.

6. Disconnect heater cable at 2 connectors (c).

Figure 4-4. Removing the Heating Module.

a

b

c

4-8


4.3.2 Replacing the Protective Glass andReflectorSwivel drying unit up and unscrew cover (d).

4.3.2.1 Removing Protective Glass and Reflector1. Pull reflector (e) up and out.

2. Pull protective glass (f) up and out.

4.3.2.2 Installing Protective Glass and Reflector

1. Insert protective glass with opening pointingdown.

2. Insert reflector.

3. Screw cover on (d).

Figure 4-5. Replacing Protective Glass.

4.3.3 Replacing the Halogen Lamp

4.3.3.1 Dismantle Halogen Lamp1. Dismantle the heating module.

2. Dismantle protective glass and reflector.

3. Use both forefingers to spread the clampingsprings to the left and right and at the same timeuse both thumbs to lift the Halogen lamp care-fully upward out of the clamping springs (the twoends ot the Halogen lamp must not be benttoward or away from each other, otherwise, theglass tube will break).

Figure 4-6. Replacing Halogen Lamp.

f

e

d

4-9


4.3.3.2 Installing the Halogen Lamp

CAUTION: Finger oils can cause premature lamp failure.Only touch the black part of the Halogen lamp! If necessary,clean the lamp with a weak organic solvent.

1. Hold the new Halogen lamp by the black endsand insert it into the two metal supports (a) at theback. If the metal supports have fallen out,replace them so that the wider part of the fork (b)is on top; the metal supports must press theHalogen lamp gently against the protective glass(c).

2. Lay the flat,connector side of the Halogen lampon the clamping springs at the front,use boththumbs to push it about 2 mm toward the backagainst the metal supports and then down toengage in the clamping springs.

3. Reconnect the 2 connectors of the Halogenlamp.

4. Install the protective glass and reflector.

5. Install the heating module.

ba

c

Figure 4-7. Installing the Halogen Lamp.

4.3.4 Replacing the Thermal OverloadDevice (Thermal cut-out switch)

NOTE: Before replacing the the thermal overloaddevice, it may have tripped and has to be reset. Referto paragraph 4.4 to reset the thermal overloaddevice.

1. Dismantle the heating module.

2. Use flat-nosed pliers to pull off the two cableconnectors.

3. Replace temperature controller (e). Do notforget the spacing washer on the heat-conduct-ing plate (d)! Do not tighten the washer too tight(1.2 Nm).

4. Tighten nut with 1.2 Nm. If the temperaturecontroller has responded,reset with finger (do

not push spring under edge of base!).

d

e

Figure 4-8. Replacing Thermal Overload Device.

4-10


4.3.5 Replacing the Temperature Sensor

1. Dismantle heating module.

2. Pull off the connector (a).

3. Remove screw (b) and (c),lift temperature sen-sor out of its holder and replace minding to

pull the sensor cable through the clamp (d)also see Figure 4-10.

4. Screw temperature sensor firmly back into placeand push connector (a) on again.

5. Install heating module.

Figure 4-9. Replacing Temperature Sensor.

4.3.6 Installing the Heating Module

1. Reconnect the 2 connecting cables (f) and (g) ofthe heater.

2. Insert the heating module into the frame andfasten with 2 screws (e).

The bare connector (f) carries the 220 Vpower supply voltage and must thereforealways be installed as shown. It must not lieoutside the heating module like connector(g).

Figure 4-10. Installing Heat Module.

b

c

d

a

e

g

f

4-11


3. Replace cover and fasten with 4 screws (a).

4. Swivel drying unit closed.

4.3.6 Installing the Heating Module (Cont.)

Figure 4-11. Replacing Cover.

4.3.7 Removing Housing Top

1. Remove pan handler, pan support, and draftshield.

2. Lift heat shield off.

3. Remove screw (a) and then lift the samplechamber, first at the front and then completely.

4. Remove the 4 screws (b) from the housing top.

Figure 4-12. Remove Housing.

a

a

b

4-12


ac

b

d

4.3.7 Removing Housing Top (Cont.)

5. Lift the front of the housing top then,using ascrewdriver, carefully unfasten the connectorsocket of the keyboard cable (b)and pull off thecable. Pull off the cable of the display (a).

6. Lift the housing top until the level indicator (d)isfree, then swivel it into the vertical positiontoward the back to rest against the open cover ofthe drying unit.

7. Pull off the connectors for the fan (a), tempera-ture sensor (b), and Halogen lamp (c).

8. Put the housing top aside out of the way.

a

b

Figure 4-13. Remove Cable from Display.

Figure 4-14. Remove Connectors.

4-13


4.3.8 Removing the Membrane Keypad

1. Remove the housing top.

2. Release the faulty membrane keypad from thecable side (h).

3. Remove any traces of adhesive (if necessary,usepure benzene).

WARNINGBenzene is highly flammable,use only in small quantities.

4.3.9 Installing the Membrane KeypadAvoid making finger marks and getting dust on the displayand window of the membrane keypad!

1. Insert the cable of the new membrane keypad.

2. Pull the covering foil off the adhesive surface.

3. Insert the membrane keypad into the depressionin the housing top, starting only with the front,right-hand corner and then with the right-handedge. Then, roll it toward the left into the depres-sion and press it down.

4. Install the housing top. (See 4.3.16)

h

Figure 4-15. Remove Membrane Keypad.

Figure 4-16. Install Membrane Keypad.

4-14


4.3.10 Replacing the display1. Remove housing top.

2. Unscrew display and remove.

3. Insert new display and fasten with screws.

4. Install housing top. (See 4.3.16)

4.3.11 Replacing the fan1. Remove housing top.

2. Unscrew screening plate from housing top.

3. Slide cable (i) out through grommet (k), removegrommet (k) from screening plate together withfan connector.

4. Replace fan,taking care to install it in the direc-tion indicated by the arrow printed on it (m).

5. Assemble the housing top: do not forget thespring (p)! (The pin triggers the safety switchoffif the housing top is opened during operation.)


7. Test safety switchoff for correct functioning:

• Start drying so the the lamp is lit.

• Open the cover of the MB45: the lampshould switch off immediately. If it doesnot, check whether the spring (p) is pressingthe safety pin upward (q):

Figure 4-17. Replacing Display.

m

p

i

k

Figure 4-18. Replacing Fan.

q

4-15


4.3.12 Replacing the CPU board1. Remove housing top.

2. Remove screening plate (a).

3. Pull off the connector to the power supply(b), carefully unfasten the socket connector ofthe weighing cell cable (c), and pull the cable out.

4. Unscrew the CPU board and remove.

5. Transfer the cell EEPROM (d) from the old CPUboard, replacing the battery (e) with a new one ifnecessary (3 V, Lithium,e.g. CR 2032).

6. Install new CPU board.

7. Install screening plate (a).

8. Re-insert cables (b)and (c) and fasten.


10. Perform weighing and temperature calibration.

11. After replacing the PC Board, refer to AppendixA and follow the instructions to configure the newPC Board.

b

a

c

de

Figure 4-19. Replacing CPU Board.

4-16


4.3.13 Replacing the power supply board1. Remove housing top.

2. Remove the screw (f) at the back of the screen-ing plate.

3. Pull off the 4 connectors for the CPU board(g), fan (i), temperature sensor (k) and lamp (m).

4. Remove screw to release ground protectioncable (h).

5. Remove the 4 screws from the power supplyboard and the 2 screws (o) from the RS232interface socket. Lift the power supply board atthe front and remove it.

6. Install new power supply board:

• First tighten the 2 screws (o) of theRS232 interface socket then the 4 screwswith toothed washers of the power supplyboard.

• Screw the eye of the ground protectioncable and the toothed washer firmly underthe head of screw (h).

7. Screw in the back screw (f) of the screeningplate.

8. Plug in the 4 connectors.

9. If necessary, replace the main fuse (r)T6.3 A/250 V or power supply (p) 500 mA/250 V.

10. Install the housing top. (See 4.3.16)

i

f

g

h

m

k

p

r

o

Figure 4-20. Replacing Power Supply Board.

4-17


d

e

a

c

b

4.3.14 Replacing the Weighing Cell

1. Remove housing top.

2. Remove screening plate (a)and seal (b).

3. Unfasten the socket connector (e) of the cell onthe CPU board and pull out the cable.

4. Unscrew weighing cell (c) and remove.

5. Install new weighing cell in reverse order.

6. Replace cell EEPROM (d).

7. Install screening plate.


9. Perform weight calibration.

Figure 4-21. Replacing Weighing Cell.

4-18


4.3.15 Replacing the Housing Base

1. Remove housing top.

2. Remove the following parts from the old housingbase and install them on the new one:

• Leveling screws

• CPU board (c).

• Power supply board (d).

• Weighing cell (e).

• Level indicator (f)

• Seals (g)

• Screening plate (h)


e

d

c

h

g

f

Figure 4-22. Replace Housing Base.

4-19


ac

b

d

4.3.16 Installing the Housing Top

1. Lay the housing top toward the back on theopened cover of the drying unit.

2. Insert connectors for fan (a), temperature sen-sor (b), and Halogen lamp (c).

3. LIft the housing top until it is above the levelindicator (d), tilt it into the horizontal position,then over the level indicator and seal and lowerit onto the housing base.

4. Plug in the cables of the display andkeyboard. Position the ferrite core (e) in theopening in the screening plate. Fasten thesocket connector with a screwdriver (f). Closethe housing top.

Figure 4-23. Install Housing Top.

e

f

Figure 4-24. Plug in Cables.

CAUTION: Verify that cables for fan (a), tem-perature sensor (b) and Halogen lamp (c) areclear from housing top when installing. Wirescan be damaged if not positioned properly andcan possibly cause damage to the MoistureAnalyzer.

4-20


4.3.16 Installing the Housing Top (Cont.)

5. Center the housing top on the housing base andfasten the 4 screws (b).

6. Insert the sample chamber (a) starting atrear, position at rear, then fasten with screw.

7. Place heat shield into position.

8. Insert draft shield, pan support, and pan handler.

9. Close cover.

Figure 4-25. Housing Top Re-assembly.

a

b

4.4 RESETTING THE THERMAL OVERLOADDEVICE

This procedure applies to units containing anaccess hole that allows the thermal overloadprotection device to be reset manually. Whenthe dryer has overheated and the thermal over-load protection has responded, it may be resetas follows:

1. Disconnect the unit from the power supply.

2. Lift the top cover straight up and remove theaccess hole cover from the access hole usinga flat head screwdriver.

3. Reset the overload device with your finger. Seeillustrations.

4. Replace the access hole cover and reconnectunit to power supply.

Figure 4-26. Resetting Thermal Overload Device.

4-21


4.5 FINAL WORK STEPS– Set original customer configuration.

– Attach peripheral units.

– Perform weight and temperature calibration.

– Adjust dryer with Ohaus temperature calibration kit, if not available, drying with a coin as sample; 160 °C for 15minutes: Display of moisture: 0.000 g ± 0.005g

4-22


5-1

CHAPTER 5 DRAWINGS AND PARTS LISTS

5.1 DRAWINGS AND PARTS LISTSThis section of the manual contains exploded views of the top housing, bottom housing and dryer unit with associated partslists.

NOTE:In all cases where a part is replaced, the Moisture Analyzer must bethoroughly checked after the replacement is made. The MoistureAnalyzer MUST meet the parameters of all applicable specifications inthis manual.

If further technical information is needed, in the United States call Ohaus Aftermarket toll-free 1-800-526-0659 between 8.00a.m. and 5:00 p.m. EST. An Ohaus factory service technician will be available to provide assistance. Outside the U.S.A.,please contact:

Ohaus Corporation19A Chapin RoadP.O. Box 2033Pine Brook, NJ 07058-2033, USATel: (973) 377-9000Fax: (973) 944-7177

5-2


5.1.1 Top Housing

Figure 5-1. Top Housing.

9

11

35

5

7

6

8 10

4

1

2

3

5-3


Item Description Part Number

1 Sample pan handler (accessory, 3 pieces) 214526

2 Sample pan holder 214642

3 Draft shield, clean out tray 214368

4 Heat shield 11113360

5 Sample chamber 11113359

6 Membrane keypad 11113356

7 Top housing with keypad (without display) 11113862

8 Display 11113772

9 Safety pin 11113367

10 Spring for safety pin 11600360

11 Fan 11113770

TABLE 5-1. SPARE PARTS LIST TOP HOUSING

5-4


5.1.2 Bottom Housing

13

14

24

21

20

22

23

15

17

18

16

19

12

Figure 5-2. Bottom Housing.

5-5


TABLE 5-2. SPARE PARTS LIST BOTTOM HOUSING

Item Description Part Number12 Seal for housing top 11113362

13 Weighing cell incl. EEPROM (Item 18) and seal 11113850

14 Seal for weighing cell 11600363

15 Power supply board 11113780

16 CPU board 11113853

17 Battery 3 V, Lithium, CR 2032 or equivalent See Note

18 Cell EEPROM 1) 11103757+SNR

19 Cable CPU – power supply 11113773

20 Bottom housing 11113350

21 Leveling screw 11101302

22 Level 11101335

23 Microfuse cap (fuse T6,3 A/250 V) 89290

24 Line cable (accessory) 6569-00, 120V US

24 Line cable (accessory) 76212-00, 220V EU

24 Line cable (accessory) 76448-00, 240V UK

24 Line cable (accessory) 76199-01, 240V AUS

1) The order has to contain the serial number SNR of the balance!

NOTE: battery is not available as a replacement part. Must source locally.

5-6


5.1.3 Dryer Unit

Figure 5-3. Dryer Unit.

36

30

35

25

26

28

27

29

32

33

34

5-7


TABLE 5-3. SPARE PARTS LIST DRYER UNIT

Item Description Part Number

25 Reflector 214382

26 Protective glass 214360

27 Halogen radiator110V 214417Halogen radiator 230V 214418

28 Heating module110V 11113500Heating module 230V 11113501

29 Temperature sensor 214349

30 Thermal overload device 214698

32 Dryer unit support 11113555

33 Dryer unit hinge left 11600358

34 Dryer unit hinge right 11600357

35 Dryer unit cable 11113771

36 Dryer unit cover 11113503

5-8


A-1

APPENDIX A SOFTWARE SERVICE TOOL INSTRUCTIONS

A. SERVICE NOTES

A.1 Software Service Tool InstructionsThis software tool is used when a new Main PCB is installed to:1. Configure the Main PCB.2. Enter balance serial number3. Install the application software

A.2 Requirements1. File: MB45 Service Tool Install.zip

2. Application Software File:a. MB45 Global 11670614x.motb. MB35 Europe 11670806x.motc. MB35 Latin America 802509712.motd. MB35 US 11670787x.mot

3. A PC running Windows 95 to XP

4. Interface cable Ohaus part number 80500525 (Serial extension cable)

A.3 Instructions and Notes1. To open click on the zip file

2. Find the setup file (Setup.exe) and click on it.

3. Follow the instructions.

4. Copy the application software file to the desktop. This is not required but will make the file easier to find later.

5. It is advisable to hook up the balance to HyperTerminal and make sure it is communicating. You will need a standard9 pin serial extension cable, Ohaus part number 80500525 to connect to your PC.

6. Find “MB45 Service Tool” in the program files and click it to start.

7. The screen below will open.

8. Match the serial port parameters to the balance. Balance defaults are shown above.

9. Click on the tab “Main Board Replacement”

SOFTWARE LEGENDMB45 GLOBAL 11670614x.MOT

MODELWHERE USED

SOFTWAREFILE REVISION

A-2


10. Click on the button that matches the balance.

11. Enter the serial number of the balance.

12. Enter the TDNR number of the balance.

Note: The serial number and TDNR number are printed on a label on the back of the balance.

13. CAUTION – Confirm the information entered above. This programming can only be done once. If you have madeand error, click the button “Abort Data Entry” then reenter the data.

14. When the above information has been confirmed click the “Start” button.

The following screen will open to indicate the new main board has been configured.

15. Click on the “Download” Tab.

16. Browse to the required Application Software file (mot file).

A-3


17. Press the start button.

18. If there is a problem press the red buttona. The red button is intended to download the data for the very first time or to a blank EEPROM. It is also intended

to be used as a last resort if the start button fails.

b. Using the start button will save the existing user’s test library, using the red button will not.

c. After the red button is clicked you will see a screen that says “Please cycle power to scale…”. At this time unplugthe scale from the AC line for about 30 seconds and plug it back in. The download will then take about 3 minutes.When it is complete the message “File download is SUCCESSFUL”(Checksum=xxxxxxx) will be displayed.If the message “Application code download has FAILED” is shown click the OK button and click the red buttonagain. The second time it should work.

A-4


When the software has been downloaded the following screen will be shown.

A.4 Error Messages

Indicates the computer can not establish a connection to the balance.

Indicates the main board has already been configured. A main board can be configured only once and can not bereconfigured.

Indicates the TDNR number does not match the balance configuration selected. Click “Abort Data Entry” then re-enter thecorrect data.

MB45 MOISTURE ANALYZER SERVICE MANUAL P/N 80250897 A

Documents

manual de servicio balanza de humedad MB45 ohaus