SERVICE MANUAL SD Series Scales
Contents
1. SD Small Model Figure 5 1 SD Series Scale Small Models Parts Ohaus Corporation www ohaus com 5 2 SD Series Scales Service Manual CHAPTER 5 PARTS LISTS amp DIAGRAMS 5 1 SD SERIES SCALES SMALL MODELS TABLE 5 1 SD SERIES SCALES SMALL MODELS PARTS Rubber Feet 4 Indicator Complete Mounting Bracket Adapter 1 Interchangeable Plug Set UK EU US AU Interchangeable Plug Set UK amp EU Drawing Item 8 SD Series Scales Service Manual 5 3 Ohaus Corporation www ohaus com 5 PARTSLISTS 8 DIAGRAMS 5 2 SD SERIES SCALES LARGE MODELS SD Large Model Figure 5 2 SD Series Scale Large Models Parts Ohaus Corporation www ohaus com 5 4 SD Series Scales Service Manual CHAPTER 5 PARTS LISTS amp DIAGRAMS 5 2 SD SERIES SCALES LARGE MODELS TABLE 5 2 SD SERIES SCALES LARGE MODELS PARTS Base Feet amp Cable Connector Base amp Connector without feet Adjustable Feet 4 Function Label LCD Display Indicator Complete Interchangeable Plug Set UK EU US AU Interchangeable Plug Set UK amp EU SD Series Scales Service Manual 5 5 Ohaus Corporation www ohaus com OHRUS 8 0 1 2 0 0 6 1 80120061 SERVICE MANUAL SD SERIES BASE amp INDICATOR2. an an ea 2 4 24 41 QUIDULVollage Test Re 2 4 PAL Resistance Test en een 2 5 2 4 3 Testing the Printed Circuit Board 2 6 CHAPTER 3 MAINTENANCE PROCEDURES 3 1 Preventive 3 1 3 1 1 Preventive Maintenance Checklist 3 1 32 Replacement of Major Components 3 1 3 2 1 Main Printed Circuit Board PCB 3 2 3 2 2 Batterf Beplacemenlesa 3 3 3 2 3 Function Label Replacement u0022420020000000nnnennennn neuen nennen en nnnnn nennen 3 3 CHAPTER 4 TESTING le ses re ee ee ee 4 1 4 2 4 1 4 3 Performance Tests Using a Scale 4 1 4 3 1 Overload Underload 4 2 4 4 Performance Tests Using a Load Cell 4 3 4 5 Galibralion Retenli
3. DO NOT ATTEMPT TO REMOVE THE TOP OF THE BASE ON SMALLER SD MODELS THE BASE AND LOAD CELL ARE NOT REPAIRABLE IF A PROBLEM ARISES ORDER A REPLACEMENT OPENING THE BASE WILL DESTROY THE INTERNAL ELECTRONIC COMPONENTS Note On larger models SD75L and SD200L the platform can be removed without destroying the internal electronic components However no parts of the base are designed to be repaired merely replaced Ohaus scales should be carefully handled stored in a clean dry area and cleaned periodically Follow these precautionary steps When an Indicator has had chemicals or liquids spilled on it all exterior surfaces should be cleaned as soon as possible with warm water on a damp cloth Allow time for the scale to stabilize after moving it from an area which is at a different temperature than the area where it is to be operated one hour for each 5 F 2 7 C change After temperature stabilization allow an additional 20 minutes after turning the scale on for the scale electronics to stabilize 3 1 1 Preventive Maintenance Checklist The Indicator should be inspected and checked regularly as follows 1 Unplug the AC Adapter before cleaning 2 Clean the outside using a damp cloth with warm water CAUTION DO NOT USE CHEMICAL CLEANERS OR SOLVENTS OF ANY TYPE SOME CLEANERS ARE ABRASIVE AND MAY AFFECT THE SCALE S FINISH 3 Check the Power Cord for broken or damaged insulation 4 Make a visual inspection for fa
4. OHAUS SERVICE MANUAL SD Series Scales Ohaus Corporation 19A Chapin Road P O Box 2033 Pine Brook NJ 07058 2033 973 377 9000 2 OHAUS SERVICE MANUAL SD Series Scales The information contained in this manual is believed to be accurate at the time of publication but Ohaus Corporation assumes no liability arising from the use or misuse of this material Reproduction of this material is strictly prohibited Material in this manual is subject to change Copyright 2008 Ohaus Corporation all rights reserved TM Registered trademark of Ohaus Corporation TABLE OF CONTENTS Page No CHAPTER 1 GETTING STARTED Il 16101152 ante ee ns ee ee ee 1 1 t2 SSSI VICE FACIES 1 1 1 3 Tools and Test Equipment Required 1 2 1 4 RS DOCIIGAU OMS ee 1 2 15 OPEO E 1 3 Power SUDOIW sense een ee ea 1 3 1 5 2 Overview or ME ee 1 3 19 3 Basier UNClIONSs sea ee een 1 4 10 4 Dynamic 1 4 1 6 91 1 5 2 TROUBLESHOOTING 2 14114610 1 se ee Eee 2 1 223 VISUAVINSDECHO 2 1 2 3 Diagnosic Gude ee E A 2 2 IS een ern nee ee aeg 2 2 2 4 checking the Load Gell S
5. 3 Examine the top ofthe PCB for cracks or signs of corrosion 4 If it appears that corrosion may have affected the board and you want to examine the bottom of the PCB remove the three screws tiny holding it to the housing 5 Carefully lift out the main PC board If it is cracked or shows signs of corrosion it requires replacement See Chapter 3 Maintenance Procedures If the Indicator shows no sign of physical damage continue with procedures see chart below for visual checking procedures CRACKED REPLACE TOP COVER INDICATOR CRACKED REPLACE BOTTOM COVER INDICATOR VISUAL CHECKS EXTERNAL amp no ASSEMBLE INTERNAL AND TEST LCD DISPLAY PARTIALLY OR Pee BLACKENED PANEL SWITCHES REPLACE NON FUNCTIONAL INDICATOR Figure 2 1 Visual Checking Procedures SD Series Scales Service Manual 2 1 Ohaus Corporation www ohaus com 2 TROUBLESHOOTING 2 3 DIAGNOSTIC GUIDE Table 2 1 is a Diagnostic Guide designed to help locate the problem area quickly and easily The probable causes are listed with the most common cause first If the first remedy does not fix the problem proceed to the next remedy Before attempting any repairs read all chapters of this manual to be familiar with overall operation and all components 2 3 1 Diagnosis 1 Isolate and identify the symptom 2 Refer to Table 2 1 Diagnostic Guide and locate the symptom 3 Follow the suggested remedies in the order they appear 4 Perform the indic
6. Remove excess weight from platform Power on Over Under load On larger models SD75L 502001 be sure platform cover is in place rar Calibration Error Stop calibration and try again after checking for correct weight Unstable at Power on Be sure environment is stable and scale is resting on a flat surface Check adjustable feet larger models EEPROM read error Replace PCB Low battery shutdown Replace batteries Low line voltage shutdown If input voltage is unstable switch to power adapter problem battery operation Display SD Series Scales Service Manual 2 3 Ohaus Corporation www ohaus com 2 TROUBLESHOOTING 2 4 CHECKING THE LOAD CELL S SIGNAL Open the Indicator by removing the four screws in the bottom housing Note Do NOT open the base on smaller models doing so will destroy the internal electronic components requiring the base to be replaced 2 4 1 Output Voltage Test Measure the no load 50 load and full load output The reading should meet the Load Cell specifications The Load Cell output should be very close to linear over its capacity range NOTE The following steps involve power applied to the scale Load Cell solder contacts can be used as measuring points See Figure 2 2 TOP VIEW OF PCB CAL LOCK Power Supply amp Battery Connector Figure 2 2 SD Series PCB connect
7. is at a different temperature than the area where it is to be operated one hour for each 5 F 2 7 C change After temperature stabilization allow an additional 20 minutes after turning the scale on for the scale electronics to stabilize 2 To select the weighing unit to be used press UNITS Cal until the correct unit is displayed then press Yes Note Calibration can be stopped at any time press UNITS Ca or turn the scale off Press and hold UNITS Ca until CAL is displayed 4 With the platform empty press ON ZERO Offto capture the scale zero The display will show C 0 m 5 After the zero is captured the required span calibration weight value in the selected unit appears 6 Place the calibration weight on the platform and press ON ZERO Off The display will again show C 7 After span capture the display will return to the normal weighing mode 51175 Ly Note The message CAL E will appear if an incorrect calibration weight was applied Repeat the procedure using the correct calibration weight Calibration Locking By use of an internal switch the calibration function may be locked disabled and unauthorized recalibration prevented 1 With the scale powered off remove the back housing section of the scale by unscrewing the four screws at the bottom 2 Slide the switch on the PCB marked 5 3 to the position marked CAL LOCK 3 Reassemble the housing 4 Ifr
8. ohaus com 1 GETTING STARTED 1 5 3 Basic Functions Power Up Test When ON ZERO Off button is pressed the scale turns on all display segments appear followed by the software version The display then resets to zero Zero Function By pressing ON ZERO Off the display returns to zero When adding additional mass press ON ZERO Off repeatedly until the scale s full capacity is reached When using a container ON ZERO Offmay be used to simulate a Tare function Additional mass may then be added as a NET weight When removing both the sample and container from the scale a negative value may appear Zero the scale again before subsequent usage Note Pressing ON ZERO Offwill perform a true zero setting function when displayed values are within 2 of full capacity Above 2 the range is limited to full capacity by subtraction Negative Values When a load is removed from the scale any previously zeroed value will be displayed as a negative number To return to normal operation press ON ZERO Off to clear the negative value Overload If the applied load exceeds the scale s capacity an appears Remove the load and the scale will return to normal operation Auto Shut Off During battery operation the scale automatically turns off after approximately four minutes of inactivity to extend battery life 1 5 4 Dynamic Weighing Also known as animal weighing this feature displays an average weight value dur
9. remove Place Load 2 on the Scale and press ON ZERO Off Place the reference mass on the Scale record the weight and remove Place Load 3 on the Scale and press ON ZERO Off Place the reference mass on the Scale and record the weight The difference in the weights of the test mass should be within the tolerance in the relevant Specification Table in Chapter 1 If not calibrate see Section 1 8 and repeat the test 9 Ifthe Scale remains out of tolerance the base may need to be replaced Ohaus Corporation www ohaus com 4 6 SD Series Scales Service Manual CHAPTER 5 PARTS LISTS amp DIAGRAMS This section of the manual contains exploded views for the SD Series Scales The exploded view drawings are designed to identify the parts which can be serviced on the balance in the field NOTE In all cases where a part is replaced the balance must be thoroughly checked after the replacement is made The balance MUST meet the parameters of all applicable specifications in this manual If further technical information is needed please contact your local Ohaus office Ohaus Corporation www ohaus com 19A Chapin Road P O Box 2033 Pine Brook 07058 2033 USA Tel 973 377 9000 Fax 973 593 0359 In the United States call toll free 800 526 0659 between 8 00 a m and 6 00 p m EST SD Series Scales Service Manual 5 1 Ohaus Corporation www ohaus com 5 PARTSLISTS 8 DIAGRAMS 5 1 SD SERIES SCALE SMALL MODELS
10. the inset latch 3 3 Sp sSerles Scaleo mallModela ns ee an 5 2 SD Series Scale Large Model anna 5 4 SD Series Scales Service Manual 2 Ohaus Corporation www ohaus com CHAPTER 1 GETTING STARTED 1 1 INTRODUCTION This service manual contains the information needed to perform routine maintenance and service on the Ohaus SD Series Scales The contents of this manual are contained in five chapters Chapter 1 Getting Started Contains information regarding service facilities tools and test equipment measuring masses specifications and the mechanical and electronic functions of the scale Chapter 2 Troubleshooting Contains a diagnosis diagnostics chart and error code table Chapter 3 Maintenance Procedures Contains preventive maintenance procedures and disassembly repair and replacement procedures Chapter 4 Testing Contains an operational test segment display test performance tests and adjustments Chapter 5 Drawings and Parts Lists Contains exploded views of SD Series Scales identifying all serviceable components Before servicing the scale you should be familiar with the Instruction Manual which is packed with every scale 1 2 SERVICE FACILITIES To service a scale the service area should meet the following requirements Must be protected from electrostatic discharge e Should be temperature controlled and meet the scale specifications for temperature environment
11. 1 Place half of the scale s capacity in the center of the Pan 2 Note the reading 3 Move the mass halfway between the center and the edge to the front of the Pan Note any differences in the displayed weight reading 4 Repeat the test for the back left and right position of the Pan 5 Maximum allowable change in displayed weight readings for each of the four positions can be found in Table 1 1 Specifications page 1 2 If this maximum is exceeded replace the base SD Series Scales Service Manual 4 5 Ohaus Corporation www ohaus com 4 TESTING 4 8 Linearity Test This test is used to determine the linearity of the unit throughout its operating range The masses used to perform this test can be utility masses NOTE The scale must pass the Repeatability and Off Center Load tests and be calibrated before the Linearity Test may be performed TABLE 4 2 LINEARITY TEST MASSES Capacity amp Readability 5035 SD75 SD75L 50200 502001 Load 2 20 kg 40 Ib 25 kg 50 Ib 100 kg 200 Ib Load 3 25 kg 50 50 kg 100 Ib 150 kg 300 Ib NOTE All masses are nominal values Be certain to use the same reference mass throughout the procedure 1 2 3 4 6 8 10 kg 20 Ib 10 kg 20 Ib 50 kg 100 Ib Place the reference mass on the Scale record the weight and remove Place Load 1 on the Scale and press ON ZERO Off Place the reference mass on the Scale record the weight and
12. al requirements See specifications for temperature range Must be free of vibrations such as fork lift trucks close by large motors etc e Work surface must be stable and level e Work surface must not be exposed to direct sunlight or radiating heat sources SD Series Scales Service Manual 1 1 Ohaus Corporation www ohaus com 1 GETTING STARTED 1 3 TOOLS AND TEST EQUIPMENT REQUIRED The service shop should contain the following equipment 1 Standard hand tools 2 Digital Voltmeter DVM 3 Load Cell Simulator optional 14 SPECIFICATIONS TABLE 1 1 SPECIFICATIONS Specification 5035 SD75 SD75L 50200 502001 Capacity x readability d 200 kg x 0 1 77 lb x 0 05 165 Ib x 0 1 440 Ib x 0 2 Maximum Displayed Resolution 1 1650 1 2200 Calibration Weights fixed 100 kg 200 Ib Operating Temperature range 5 C 41 F to 40 C 104 F at 10 to 80 relative humidity non condensing Storage temperature range 10 C 14 F to 60 C 140 F at 10 to 80 relative humidity non condensing Static over load limit load cell alkaline batteries not included Ohaus Corporation www ohaus com 1 2 SD Series Scales Service Manual CHAPTER 1 GETTING STARTED 1 5 OPERATION This section contains information on the basic operation of the SD Series Scale Exploded view drawings in Chapter 5 identify all components 1 5 1 Power Supply Power to the scale is supplied by a 9 V dc 100mA Power Adapter or
13. alibration with zero at the simulators zero setting and 100 capacity at the simulator s millivolt setting in Table 2 3 page 2 5 2 Following calibration check that the Indicator s display reading is stable at each simulator level up to the maximum set in the calibration If the readings are stable the Indicator is functioning properly 4 5 Calibration Retention Test This test checks that the Indicator retains calibration after power is removed and then restored 1 Turn the Indicator OFF and disconnect the AC Adapter 2 Wait one minute then reconnect the AC Adapter to the Indicator 3 Check to insure that the Indicator retained calibration settings Ohaus Corporation www ohaus com 4 2 SD Series Scales Service Manual 4 TESTING 4 6 Repeatability Test Repeatability is the Standard Deviation of a set of similar weight readings Requirements To perform this test a single mass must be used for all readings The test mass should be approximately 1 2 of the capacity of the scale Before starting a repeatability test set up the scale as follows Set Up Enter the menu and set the scale to display the same units as the performance specifications TEST PROCEDURE 1 Zero the scale 2 Using atest mass approximately half the capacity of the scale place the mass on the center of platform Record the reading on the worksheet provided Remove the mass from the platform Repeat this test startin
14. ated checks or see the appropriate section of the manual 5 Repair or replace the defective part NOTE lf more than one symptom is observed approach one area at a time and remember that the symptoms may be interrelated lf a problem arises that is not covered in this manual contact Ohaus Corporation for further information Ohaus Corporation www ohaus com 2 2 SD Series Scales Service Manual 2 TROUBLESHOOTING 2 3 1 Diagnosis TABLE 2 1 DIAGNOSTIC GUIDE TABLE Scale will not turn on No power to scale Verify connections and voltage Battery power used up Connect power and replace batteries Poor accuracy Improper calibration Perform calibration Unstable environment Move scale to suitable location Unable to calibrate Unstable environment Move the scale to suitable location Incorrect calibration mass Use correct calibration mass No display or Power cable is defective Check power cable AC LED is off Batteries are defective Replace batteries Low Bat LED is lit Batteries are weak Replace the batteries Display Scale is in Dynamic Weighing Proceed weighing in Dynamic Mode Weighing Mode if desired See Section 1 7 To exit remove the mass from the platform and press UNITS Cal Display Load cell cable is disconnected Connect the load cell cable to the 999999 or no Dale Aion reading No calibration data in EEPROM Calibrate the Indicator Display Over load Under load
15. by size LR 14 alkaline batteries The batteries allow the unit to run for 360 hours When both the line voltage and battery are present the scale will take power from line voltage When line voltage is lost the scale will automatically switch over to battery operation The unit will power off after four minutes of inactivity when running on battery Battery indicator is on when battery is in use Low Battery Flashing battery symbol indicates a low battery condition When first displayed approximately 12 hours of operation remain When the battery 16 fully depleted the scale momentarily displays Lo bAt and shuts off 1 5 2 OVERVIEW OF THE CONTROLS Battery Indicator _ Control Buttons UNITS Cal 2 Off segment 4 digit LED display Figure 1 1 SD Series Display ON ZERO Off key A short press turns on the scale when it is off When the scale on a short press zeroes the scale and a long press turns the scale off UNITS Cal key A short press changes the weighing unit and weighing mode In Dynamic Weighing Mode a short press initiates countdown Along press initiates calibration Stability Indicator A appears in the left corner when the reading is stable Weighing Unit The selected weighing unit selected appears on the right Dynamic Weighing Mode flashes next to the selected weighing unit SD Series Scales Service Manual 1 3 Ohaus Corporation www
16. e out of tolerance replace the base TABLE 2 3 LOAD CELL OUTPUT READINGS in mV with Excitation Model Capacity 50 Load 100 Load 2 4 2 Resistance Test Perform a Resistance Test to determine if the Load Cell is severely damaged or a short circuit has occurred Note The Load Cell must be completely disconnected from the Printed Circuit Board and at no load when the resistance readings are taken Using an ohm meter measure and record resistance between each pair of wires from the Load Cell as specified in Table 2 2 Compare the measured readings with the specified values in Table 2 4 If the resistance readings are in the range specified skip to the next section If they are outside the expected range open circuit or short circuit across any two wires the Load Cell is defective replace the base TABLE 2 4 LOAD CELL RESISTANCE READINGS in Ohms Model Exe to Ex S to S Exe to 8 to S Ex 10S SD Series Scales Service Manual 2 5 Ohaus Corporation www ohaus com 2 TROUBLESHOOTING 2 4 3 Testing the Printed Circuit Board The PCB can be tested by measuring voltages and by using a simulator The simulator replaces the Load Cell during testing and is a useful tool for diagnosing problems PCB Voltage Measurements Note Prior to the voltage measurements test and install new batteries 1 Disconnect the power and remove the Top Housing 2 Connect the AC Adapter to t
17. e protective backing from the back of the new Function Label and carefully position it on the Top Housing starting at the bottom of the Housing Use a rolling motion to smooth the Function Label into position SD Series Scales Service Manual 3 3 Ohaus Corporation www ohaus com 3 MAINTENANCE PROCEDURES Ohaus Corporation www ohaus com 3 4 SD Series Scales Service Manual 4 TESTING 4 1 TESTING Before and after servicing the Indicator operational and performance tests should be made to determine if it meets specifications Turn the Indicator ON and allow it to warm up for at least 20 minutes before performing these checks The masses used for calibration should be ASTM Class F or OIML Class M1 tolerance or better NOTE Make sure the test area 15 free from drafts and that the base rests on a level and vibration free surface 4 2 Power Test The purpose of this test is to determine if the electronic circuitry of the Indicator is functioning properly or not 1 Connect a functioning AC Adapter to the Indicator power plug 2 Plug the AC Adapter into a suitable power source 3 With the Indicator connected to an appropriate power supply press the ON ZERO OFF button The Indicator performs a self test indicates the software revision and then goes into weighing mode 4 If all of the displays appear normal in this test continue with the next test If the display did not appear check the AC adapter out
18. equired place tamper evident seals over the screw holes or the housing edges If later recalibration is required the housing will need to be reopened and the lock switch returned to the original position Note When the lock switch is set to the CAL LOCK position the power on zero range is reduced to 10 of full capacity SD Series Scales Service Manual 1 5 Ohaus Corporation www ohaus com 1 GETTING STARTED Ohaus Corporation www ohaus com 1 6 SD Series Scales Service Manual 2 TROUBLESHOOTING 2 1 INTRODUCTION This section of the manual covers visual inspection troubleshooting and a Diagnostic Guide Table 2 1 Follow all directions step by step Make certain that the work area is clean and use care when handling components of the Indicator 2 2 VISUAL INSPECTION Carefully remove the Base and Indicator from its packing container and remove any packing material Note all items supplied with the unit such AC power supply cables instruction manual weights etc Keep a record of all items and note their condition 1 Examine the Indicator for signs of abuse such as a cracked top cover or base damage from liquids cracks on corners which may suggest the unit was dropped 2 Open the Indicator by removing the four screws in the bottom housing Note Do NOT open the base on smaller models doing so will destroy the internal electronic components requiring the base to be
19. g at Step 1 until you record a total of ten readings Fill in the worksheet Table 4 1 with the ten readings SD Series Scales Service Manual 4 3 Ohaus Corporation www ohaus com 4 TESTING 4 6 Repeatability Test TABLE 4 1 REPEATABILITY WORKSHEET Delta Reading Mean Delta x Delta n number of Reading Mean Sum of readings 10 Delta Reading Mean Standard Deviation Square Root of sum of Delta x Delta 9 5 Addthe ten readings and divide the total by 10 to find the Mean average Mean Reading 1 Reading 2 Reading 3 Reading 4 Reading 5 Reading 6 Reading 7 Reading 8 Reading 9 Reading 10 10 Mean 6 Calculate the Delta for each reading and record in the work sheet Delta Reading Mean Calculate the Delta x Delta for each reading and record in worksheet 8 Add the ten Delta x Delta values and divide by 9 Calculate the Standard Deviation by applying the square root of the result from step 8 Standard Deviation Note If the scale does not meet specifications move it to a suitable location ensure that it is level and try again If it still does not meet specifications replace the base Ohaus Corporation www ohaus com 4 4 SD Series Scales Service Manual 4 TESTING 4 7 Off Center Load Test The Off Center Load Test is used to determine whether displayed weight values are affected by moving the sample to different areas of the Pan
20. he Indicator and turn it on 3 Using a DVM measure the excitation voltage EXE and EXE in Figure 2 1 The reading should be 3 volts dc This is the excitation voltage for the Load Cell and is regulated If the voltage is lower replace the PCB See Chapter 3 Then perform Operational Tests See Chapter 4 4 Measure incoming power from the AC Adapter Connector See Figure 2 1 It should read between 9 and 14 volts dc with power off and above 9 Volts with power on 5 Perform simulator testing Simulator Testing To perform these tests the use of a Simulator is required The function of a Simulator is to simulate the output of a full bridge Load Cell allowing the scale to be separated from the Load Cell for the purposes of troubleshooting and calibration General Load Test This test checks the Main PC Board circuitry by simulating accurate Load Cell voltages at zero load 50 and 100 load capacities 1 Disconnect power from the Indicator and remove the Top housing Remove the batteries 2 Disconnect the Load Cell cable from the PC Board 3 With the Simulator set to zero attach it to the PCB using the Load Cell Cable solder points on the PCB See Figure 2 1 4 Connect a known good AC Adapter to the Indicator and connect to a power source 5 Turnon the Indicator An under load error may appear This is normal 6 Set the Indicator to indicate weight in kilograms kg and set the calibration value to maxi
21. ing a period of several seconds Follow these steps to start and complete a Dynamic Weighing process 1 With the platform empty press UNITS Cal until the indicator flashes next to the desired measuring unit 2 Place a mass on the platform The scale will show Note If using a container press ON ZERO Off to tare the weight and return to zero 4 With a mass on the platform or container short press UNITS Ca to start the averaging countdown from 5 seconds 1 5 The averaged weight appears The indicator stops flashing when the process is complete le JH 6 The display will hold until a button is pressed 7 To repeat the process press UNITS Cal with a mass on the platform or container 8 To exit remove the mass from the platform or container and press UNITS Cal Ohaus Corporation www ohaus com 1 4 SD Series Scales Service Manual CHAPTER 1 GETTING STARTED 16 CALIBRATION For best results calibrate the scale at regular intervals Correct calibration weights must be available before starting calibration See Specification Table Multiple weights may be used to equal the required calibration weight Calibration is unavailable in Dynamic Weighing Mode CAUTION BE CAREFUL HANDLING CALIBRATION WEIGHTS THEY ARE VERY A N HEAVY IMPROPER LIFTING METHODS OR MISUSE OF CALIBRATION WEIGHTS MAY RESULT IN PERSONAL INJURY 1 Allow time for the scale to stabilize after moving it from an area which
22. ions AN The EXE EXE wires should be connected to the PCB and the SIG and SIG wires must be disconnected Record the colors for each wire connection before disconnecting See Table 2 2 for typical color code for SD Series TABLE 2 2 COLOR CODE FOR LOAD CELL WIRING WHITE GREEN YELLOW RED Color codes may vary 1 Power on the Indicator with AC Adapter 2 Using a voltmeter with no load on the Platform measure the voltage across points 1 and 4 of Load Cell connection on the PCB EXE and EXE This voltage must be approximately 3 0 Volts dc If the voltage is lower disconnect the Load Cell cable from the PCB and measure again If the voltage is 3 Volts dc the Load Cell is defective and must be replaced If the voltage remains low the PCB is defective and must be replaced CAUTION IN THE NEXT STEP DO NOT OVERLOAD THE SCALE BEYOND FULL CAPACITY RATING Ohaus Corporation www ohaus com 2 4 SD Series Scales Service Manual 2 TROUBLESHOOTING 2 4 1 Output Voltage Test Measure the voltages on SIG and SIG wires disconnected from PCB Note Measurements must be made with these wires disconnected from the PCB These measurements represent the output of the Load Cell Record measurements at Zero Load 50 and full scale capacities See Table 2 3 for typical readings NOTE Table 2 3 indicates typical readings Actual values can vary but should remain linear throughout the range If readings ar
23. mum span value 7 Adjust the Simulator to simulate 0 load 50 load and 100 load for the capacity that the unit is rated for See Table 2 3 for values to use If the resulting readings are unstable the Main PC Board is defective 8 Use the Simulator to calibrate the scale in the next procedure Ohaus Corporation www ohaus com 2 6 SD Series Scales Service Manual 2 TROUBLESHOOTING 2 4 3 Testing the Printed Circuit Board Calibration Test This test calibrates the scale using the simulator and can verify that the Main PC Board is functioning properly or improperly 1 With the scale on press and hold UNITS Ca to perform a calibration See Section 1 8 2 Follow the scale prompts When the scale indicates a given weight to be placed on the scale set the simulator to an equivalent value based on Table 2 3 3 Upon completion of calibration the PCB can be further checked using the Simulator to simulate various weight values If simulator settings and weight readings on the scale agree the PCB 15 functional If the scale readings vary or do not agree with readings in Table 2 3 the Main PC Board is defective and should be replaced See Chapter 3 SD Series Scales Service Manual 2 7 Ohaus Corporation www ohaus com 2 TROUBLESHOOTING Ohaus Corporation www ohaus com 2 8 SD Series Scales Service Manual 3 MAINTENANCE PROCEDURES 3 1 PREVENTIVE MAINTENANCE CAUTION
24. on Testasssen seele 4 3 46 4 3 Ad OIEGENtEr Load ae 4 5 Linearny 4 6 5 PARTS LISTS 8 DIAGRAMS 5 1 SD 6885 5086 Small een 5 3 5 2 SD Series Scale Large MOGE rrenat E eS 5 5 Ohaus Corporation www ohaus com 1 SD Series Scales Service Manual TABLE NO 1 1 31 2 2 2 3 2 4 4 1 4 2 5 1 5 2 FIGURE NO 1 1 2 1 2 2 3 1 3 2 5 1 5 2 TABLE OF CONTENTS LIST OF TABLES TITLE Page No SPECE ersehen 1 2 Diagnostic Guide rn ee reellen 2 3 Color Gode For Load Cell Wiring eu ee 2 4 Load Cell Output Readings in mV with 3V 2 5 Load Cell Resistance Readings in ORMS 2 5 Repeatability Worksheet una 4 4 Linearity EST MaS SES onanera 4 7 SD Series Scale Small ie 5 3 SD Series Scale Large Model 5 5 LIST OF ILLUSTRATIONS TITLE Catapult 1000 Displays aan Na 1 3 VISUalGHECKING Procedures nee 2 1 Catapult 1000 POB 5 ee 2 4 Load Cell leads are soldered to the Printed Circuit Board 3 2 Open Battery Compartment door by pressing
25. put and repeat the test with a good adapter If the display was erratic the PC board is defective and requires replacement 4 3 Performance Tests Using a Scale Base These tests are performed on the Indicator using a Known good scale base and test mass At this point the Indicator has been checked for full display menu setup and calibrated lf a Load Cell Simulator is being used proceed to paragraph 4 4 SD Series Scales Service Manual 4 1 Ohaus Corporation www ohaus com 4 TESTING 4 3 1 Overload Underload Test This test determines if the Indicator displays the proper indication when an overload condition exists on the base 1 Place a mass on the base platform which exceeds the scale s capacity and observe the Indicator display The display should indicate Error E Remove the mass from the scale base The display should return to zero 2 On larger models SD75L and 502001 test for an underload condition as follows with the Indicator ON and no mass on the scale base lift up on the base platform and observe the display The display should indicate Error E Release the platform The display should return to zero 4 4 Performance Tests Using a Load Cell Simulator A simulator can be used in place of a base if available Connect the simulator s leads to the PCB See Figure 2 2 and Table 2 2 page 2 4 Test the Indicator as follows 1 Set the simulator to zero Power on the Indicator Perform a Span C
26. ubber cement securing the cable sets to the Bottom Housing CAUTION When handling the grasp it by the edges only Do not touch the foil side Static discharge may damage some components 6 Open replacement Indicator 7 Install base cable into Housing as shown in Figure 3 1 8 Re solder the cable sets removed in Steps 4 and 5 9 Perform calibration procedures See Section 1 8 10 Perform testing procedures See Chapter 4 Ohaus Corporation www ohaus com 3 2 SD Series Scales Service Manual 3 2 2 3 2 3 3 MAINTENANCE PROCEDURES Battery Replacement 1 After placing the batteries as To replace the Type C LR14 batteries press the inset latch lever in the middle of the Bottom Housing Note the proper direction for inserting new batteries printed on the inside of the Battery Compartment door indicated close the Battery Compartment door Figure 3 2 Open Battery Compartment door by pressing the inset latch lever Function Label Replacement 2 Unplug the Indicator from the Adapter Lift the Function Label off from the Top Housing Remove the old Display Window The Function Label is held in place with a strong adhesive Clean the Top Cover and remove all traces of adhesive CAUTION Be careful placing the Function Label into position as the adhesive will not allow repositioning once attached to the cover Put the new Display Window in place Remove th
27. ulty connectors wiring and loose hardware 3 2 REPLACEMENT OF MAJOR COMPONENTS The decision to replace any component should only be made after thoroughly diagnosing the problem If after the replacement of any component the unit is still non functional and no other information on the subject is available in the manual contact your local Ohaus office or contact Ohaus Corporation by visiting www ohaus com In the United States Ohaus Aftermarket toll free 800 526 0659 between 8 00 a m and 4 00 p m EST SD Series Scales Service Manual 3 1 Ohaus Corporation www ohaus com 3 MAINTENANCE PROCEDURES 3 2 1 Printed Circuit Board Replacement Repairs are not recommended on the Indicator Component parts of the Indicator are not stocked by Ohaus Replacement is recommended rather than repairing Replace the Indicator for any of the following reasons Display is defective characters missing or partial display Indicator fails to calibrate properly Display is erratic or unstable Indicator does not operate at all Base Cable path serves as Strain relief Figure 3 1 Load Cell leads are soldered to the Printed Circuit Board 1 Unplug the power Adapter from the Indicator Remove the four screws from the Bottom Housing Carefully separate the Top Housing and Bottom Housing Unsolder the Load Cell Cable s leads from the PCB See Figure 3 1 te amp Y If necessary remove the r
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