OHAUS SD Series, Service Manual

Page 1: ...SERVICE MANUAL SD Series Scales Ohaus Corporation 19A Chapin Road P O Box 2033 Pine Brook NJ 07058 2033 973 377 9000 ...

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Page 3: ... 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 ...

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Page 5: ...ircuit Board PCB 2 6 CHAPTER 3 MAINTENANCE PROCEDURES 3 1 Preventive Maintenance 3 1 3 1 1 Preventive Maintenance Checklist 3 1 3 2 Replacement of Major Components 3 1 3 2 1 Main Printed Circuit Board PCB Replacement 3 2 3 2 2 Battery Replacement 3 3 3 2 3 Function Label Replacement 3 3 CHAPTER 4 TESTING 4 1 Testing 4 1 4 2 Power Test 4 1 4 3 Performance Tests Using a Scale Base 4 1 4 3 1 Overload...

Page 6: ...est Masses 4 7 5 1 SD Series Scale Small Model 5 3 5 2 SD Series Scale Large Model 5 5 LIST OF ILLUSTRATIONS FIGURE NO TITLE 1 1 Catapult 1000 Display 1 3 2 1 Visual Checking Procedures 2 1 2 2 Catapult 1000 PCB connections 2 4 3 1 Load Cell leads are soldered to the Printed Circuit Board 3 2 3 2 Open Battery Compartment door by pressing the inset latch lever 3 3 5 1 SD Series Scale Small Model 5 ...

Page 7: ... 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 ...

Page 8: ... features Calibrate in kg or lb Calibration lock via internal switch Weighing Units Kg lb Application Modes Weigh Dynamic Weighing Linearity 1 d 1 d 1 d Repeatability std Dev 1 d Off center load cap dist 3 d Operating Temperature range 5o C 41o F to 40o C 104o F at 10 to 80 relative humidity non condensing Storage temperature range 10o C 14o F to 60o C 140o F at 10 to 80 relative humidity non cond...

Page 9: ... battery condition When first displayed approximately 12 hours of operation remain When the battery is fully depleted the scale momentarily displays Lo bAt and shuts off 1 5 2 OVERVIEW OF THE CONTROLS SD Stability Indicator Battery Indicator Control Buttons 7 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...

Page 10: ... value Overload If the applied load exceeds the scale s capacity an E 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 during a period of...

Page 11: ...atform empty press ON ZERO Off to capture the scale zero The display will show C 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 Note The message CAL E will appear if an incor...

Page 12: ...CHAPTER 1 GETTING STARTED Ohaus Corporation www ohaus com 1 6 SD Series Scales Service Manual ...

Page 13: ...ks 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 replaced 3 Examine the top of the PCB for cracks or signs of corrosion 4 If it appears that corrosion may have affected the board and you want to exam...

Page 14: ...omponents 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 indicated checks or see the appropriate section of the manual 5 Repair or replace the defective part NOTE If more than one symptom is observed approach one area at a time and remember that the symptoms may b...

Page 15: ...ired See Section 1 7 To exit remove the mass from the platform and press UNITS Cal Display 000000 or 999999 or no weight reading Load cell cable is disconnected No calibration data in EEPROM Connect the load cell cable to the Indicator Calibrate the Indicator Display E Over load Under load ower on Over Under load P Remove excess weight from platform On larger models SD75L SD200L be sure platform c...

Page 16: ...d 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 EXE SIG SIG EXE 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...

Page 17: ...o 1 5 Zero 2 9 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 ...

Page 18: ...ction 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...

Page 19: ...en 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 is functional If the scale readings vary or do not agree with readings in Table 2 3 the M...

Page 20: ...CHAPTER 2 TROUBLESHOOTING Ohaus Corporation www ohaus com 2 8 SD Series Scales Service Manual ...

Page 21: ... 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...

Page 22: ...train relief 1 Unplug the power Adapter from the Indicator 2 Remove the four screws from the Bottom Housing 3 Carefully separate the Top Housing and Bottom Housing 4 Unsolder the Load Cell Cable s leads from the PCB See Figure 3 1 5 If necessary remove the rubber cement securing the cable sets to the Bottom Housing CAUTION When handling the PCB grasp it by the edges only Do not touch the foil side...

Page 23: ...cator from the AC Adapter 2 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 3 Put the new Display Window in place 4 Remove t...

Page 24: ...CHAPTER 3 MAINTENANCE PROCEDURES Ohaus Corporation www ohaus com 3 4 SD Series Scales Service Manual ...

Page 25: ...er 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 output and repeat t...

Page 26: ...n 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 Calibration with zero at the simulator s 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 readi...

Page 27: ...lows 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 a test mass approximately half the capacity of the scale place the mass on the center of platform Record the reading on the worksheet provided 3 Remove the mass from the platform 4 Repeat this test starting at Step 1 until you record a total of ten readin...

Page 28: ...ading 8 Reading 9 Reading 10 10 Mean ________ 6 Calculate the Delta for each reading and record in the work sheet Delta Reading Mean 7 Calculate the Delta x Delta for each reading and record in worksheet 8 Add the ten Delta x Delta values and divide by 9 9 Calculate the Standard Deviation by applying the square root of the result from step 8 Standard Deviation ___________ Note If the scale does no...

Page 29: ...e 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...

Page 30: ...alues Be certain to use the same reference mass throughout the procedure 1 Place the reference mass on the Scale record the weight and remove 2 Place Load 1 on the Scale and press ON ZERO Off 3 Place the reference mass on the Scale record the weight and remove 4 Place Load 2 on the Scale and press ON ZERO Off 5 Place the reference mass on the Scale record the weight and remove 6 Place Load 3 on th...

Page 31: ...ughly 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 or Ohaus Corporation www ohaus com 19A Chapin Road P O Box 2033 Pine Brook NJ 07058 2033 USA Tel 973 377 9000 Fax 973 593 0359 In the United States call toll free 800 526 0659 between 8 00 ...

Page 32: ...CHAPTER 5 PARTS LISTS DIAGRAMS 5 1 SD SERIES SCALE SMALL MODELS Figure 5 1 SD Series Scale Small Models Parts Ohaus Corporation www ohaus com 5 2 SD Series Scales Service Manual ...

Page 33: ...ARTS Drawing Item Description 1 Base Cable Connector 3 Rubber Feet 4 4 Function Label 5 LCD Display 6 Battery Cover 7 Indicator Complete 8 Mounting Bracket 80 Adapter 81 Interchangeable Plug Set UK EU US AU 82 Interchangeable Plug Set UK EU SD Series Scales Service Manual 5 3 Ohaus Corporation www ohaus com ...

Page 34: ...CHAPTER 5 PARTS LISTS DIAGRAMS 5 2 SD SERIES SCALES LARGE MODELS Figure 5 2 SD Series Scale Large Models Parts Ohaus Corporation www ohaus com 5 4 SD Series Scales Service Manual ...

Page 35: ...scription 1 Base Feet Cable Connector 2 Base Connector without feet 3 Adjustable Feet 4 4 Function Label 5 LCD Display 6 Battery Cover 7 Indicator Complete 8 Mounting Bracket 80 Adapter 81 Interchangeable Plug Set UK EU US AU 82 Interchangeable Plug Set UK EU SD Series Scales Service Manual 5 5 Ohaus Corporation www ohaus com ...

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Page 37: ... 80120061 P N 80120061 SERVICE MANUAL SD SERIES BASE INDICATOR ...