OHAUS EC Series, Service Manual

Page 1: ...Ohaus Corporation 19A Chapin Road P O Box 2033 Pine Brook NJ 07058 973 377 9000 EC SERIES SCALES SERVICE MANUAL...

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Page 3: ...ration assumes no liability arising from the use or misuse of this material Reproductionofthismaterialisstrictlyprohibited Material in this manual is subject to change Copyright 2005 Ohaus Corporation...

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Page 5: ...g and Calibration 3 1 3 1 Testing the AC Adapter 3 1 3 2 Testing the Membrane Switch 3 1 3 3 Testing the Load Cell Assembly 3 2 3 3 1 Resistance Test 3 2 3 3 2 Excitation and Output Voltage Test 3 2 3...

Page 6: ...Assembly with frame 4 9 4 5 Replacing the Load Cell Component 4 11 4 5 1 Overload Protection Stop Adjustment 4 12 4 6 Replacing the Battery 4 13 CHAPTER 5 PARTS LISTS 5 Parts Lists 5 1 5 1 EC Series...

Page 7: ...ration Chapter 4 Repair Procedures Contains detailed repair procedures for all major components Chapter 5 Parts Lists Contains overall views identifying all major serviceable replacement components wi...

Page 8: ...st the EC Series Scales must meet the requirements of ASTM Class 4 or OIML Class F2 The mass values are listed in Table 1 1 TABLE 1 1 CALIBRATION MASSES MODEL Calibration Cal in kg MassesTotaling EC3...

Page 9: ...l types of problems that could be encountered with the scale The troubleshooting tables refer to an interconnection diagram in Section 3 to assist in locating the problem 2 1 SCALE WILL NOT TURN ON WI...

Page 10: ...d lead and0ohmsfortheblacklead Ifanopen conditionexists replacewiringandcon nector as necessary If OK proceed Refer to Section 3 2 and test the Mem brane Switch Replace if necessary See Repair Procedu...

Page 11: ...r proceedwithPerformanceTestsinSec tion 3 6 TABLE 2 4 NO DISPLAY OR PARTIAL DISPLAY SYMPTOM Displayisnotonorpartialchar acters are displayed PROBABLE CAUSE Display PC Board is defec tive or LCD may be...

Page 12: ...uld be tested in accordancewithSection3 4 TheMain PC Board if defective should be re placed See Repair Procedures 4 3 After repair proceed with performance Tests in Section 3 6 SYMPTOM Scale can be tu...

Page 13: ...tly Ensure the Pan is empty before switching the scale on Test the Load Cell refer to Section 3 3 If defective replace see Section 4 4 After repair proceedwithPerformanceTestsin Section 3 6 The Main P...

Page 14: ...2 6 CHAPTER 2 DIAGNOSIS...

Page 15: ...the voltage on the battery terminals Turn the scale on The voltage should be 6 5 Volts dc minimum and 7 5 Volts dc maximum If the voltage is below or above these readings replace the Adapter This is t...

Page 16: ...DING Wires 2 5 415 15 Ohms Wires 3 4 350 3 Ohms NOTE Wires 2 3 4 and 5 must be isolated from chassis ground and shield Resistance should be greater than 5 megohms A lower reading indicates a short in...

Page 17: ...e 3 3 indicates typical readings actual values can vary but should remain linear throughout the entire range If readings are out of tolerance replace the Load cell See Section 4 4 or 4 5 for Load Cell...

Page 18: ...ure 3 2 Interconnection Diagram which illustrates the interconnections to the Main PC Board and is shown as a top view 7 Turn the scale on 8 Using a DVM measure the excitation voltage across EXE and E...

Page 19: ...ng test leads in place of the load cell Make sure connections are correct 6 Connect a known good AC Adapter to the scale and connect to a power source 7 Turn on the scale an error may be displayed Thi...

Page 20: ...DoNOTdisposeofthebatteryinincinerators orcrushortrytoopen Disposeofthe defective battery in accordance with local regulations for lead acid type batteries CAUTION Checkthebatteryforanysignofirregular...

Page 21: ...voltage should be above 6 0 Volts dc ten minutes after charging stops NOTE If the scale operates less than 80 hours charge the battery and turn on the scale and test how long the scale operates If the...

Page 22: ...d Units ____________ Zero Return ____________ Mass Used ____________ Accurate performance of the EC Series Scales is determined by a series of three performance tests Repeatability Test Off Center Loa...

Page 23: ...ng Mean Sum of Readings 10 Delta Reading Mean Standard Deviation The Square root of the sum of the Delta x Delta 9 5 Add the ten readings and divide the total by 10 to find the Mean average Mean Readi...

Page 24: ...o return the reading to zero 5 Slide the mass halfway between the center and the left edge of the platform and record the reading 6 Slide the mass to the center of the weighing surface and press the Z...

Page 25: ...s to the center of the platform and record the exact value displayed 6 Remove the reference mass and verify that the display returns to zero If it does not disregard the reading press ZERO to rezero t...

Page 26: ...l scale capacity ________________ Reading 3 reference weight added at 1 2 full scale capacity ________________ Reading 4 reference weight added at 3 4 full scale capacity ________________ CalculateDif...

Page 27: ...mulation Battery status Memories 10 locations for APW Keyboard 7 function 11 numeric x Membrane switch Tare Sample APW Zero Pre set Tare M Cancel Zero Range 4 of Full Scale Capacity Tare Range Full Ca...

Page 28: ...CAL is displayed in the Count window 2 The required calibration weight is displayed ex 3000g for a 3kg model At this time a different calibration weight value can be entered via the numeric keypad 3 P...

Page 29: ...l d scale division d scale division t rAtE 0 1 2 3 4 5 Level bL 0 Auto On 1 Manual Unit 0 Grams g 1 Pounds lb AU 0 Off 1 On Auto Off Sets the period of inactivity before the scale automatically turns...

Page 30: ...3 16 CHAPTER 3 SCALE TESTING AND CALIBRATION...

Page 31: ...the AC adapter Make sure the scale is off 2 Carefully lift and remove the Pan and Pan Support from the scale 3 Turn the scale over and remove the five screws which hold the Top Housing Refer to Figur...

Page 32: ...tions 1 Refer to Section 4 1 and remove Top Housing CAUTION Use care in the next step as the Display PCB wiring is attached to the PC board 2 Place the scale in the upright position and carefully lift...

Page 33: ...hrough the hole in the Top Housing Peel off the protective film from the new Membrane Switch and carefully align and affix to the Top Housing 8 Press the Membrane Switch down uniformly Using your fing...

Page 34: ...uitry and the Battery if the wiring is accidentally shorted during servicing Figure 4 5 Battery Terminal Connector Note the positioning of the cable for reassembly 3 Remove the screws and washers hold...

Page 35: ...ing is installed in the correct locations 10 Connect the Display Cable to the Main PC Board connector See Figure 4 8 CAUTION THE DISPLAY CABLE CONNECTOR MUST BE CORRECTLY INSTALLED WITH THE TAB FACING...

Page 36: ...efer to Figure 4 9 and move the Main PC Board Jumper from normal to service position NORMAL SERVICE Figure 4 9 Main PC Board Jumper Positions 14 Position the Top Housing in place over the scale tempor...

Page 37: ...Switch Cable from the Display PC Board 3 Disconnect the Membrane Switch Cable from the Display PC Board See Figure 4 11 Figure 4 10 Disconnecting the Ribbon Cable 4 Remove the six screws that hold th...

Page 38: ...ledamagesuchasacrackedglassorpartial display and the scale operates normally in all other functions NOTE This procedure is very difficult and should not be attempted unless you have the proper tools 1...

Page 39: ...be checked before installation 1 Refer to Section 4 1 and remove Top Housing 2 Turn the scale over and remove the four feet by unscrewing them counter clockwise The feet are actually screwed into the...

Page 40: ...position in the slots on the Bottom Housing and secure with the screws and washers previously removed 12 Refer to Figure 4 15 and move the Main PC Board Jumper from normal to service position 4 4 REPL...

Page 41: ...tery wires together with the Load Cell cable 3 Remove the Load Cell by unscrewing two bolts on the top of the Load Cell and two bolts on the bottom of the Load Cell See Figure 4 16 Figure 4 16 Load Ce...

Page 42: ...sert the proper feeler gauge as specified in Table 4 2 2 With the correct feeler gauge positioned in the first Overload Protection Stop press down on the Frame and see if there is movement of the fram...

Page 43: ...used when it is required to change the Battery WARNING DEATH OR SERIOUS INJURY CAN OCCUR Charge the battery only with the charger in the scale Charging the battery under any other conditions may caus...

Page 44: ...e Top Housing is installed the Battery is held in place CAUTION Dispose of the Battery according to local regulations for hazardous materials Do not incinerate crush or throw out in regular garbage co...

Page 45: ...t is made The scale MUST meet the parameters of all applicable specifications in this manual If further technical information is needed in the United States call toll free 1 800 526 0659 between 8 00...

Page 46: ...MBLED TOP HOUSING OPEN MEMBRANE SWITCH P N 80120005 P N 80010589 ECJP DISPLAY PCB P N 80104178 Scales older than SN 8026532998 require a new Main PCB FEET P N 80120032 1 Pc BOTTOM HOUSING P N 80120024...

Page 47: ...N 8026532998 require a new Display PCB BOTTOM HOUSING OPEN Figure 5 2 Components in Bottom Housing of EC Series Scales BATTERY P N 80120026 DISPLAY CABLE P N 80120022 LOAD CELL TOP FRAME P N 80120039...

Page 48: ...Loadcell EC15 80120016 Loadcell EC30 80120017 Loadcell assembly EC3 80120018 Loadcell assembly EC6 80120019 Loadcell assembly EC15 80120020 Loadcell assembly EC30 80120021 Power switch assembly 801200...

Page 49: ...ervice Menu Diagram A 1 ENTERING THE SERVICE MENU 1 Turn the scale on Note The password must be entered during the scale self test in the next step 2 The Service menu is accessed by entering the passw...

Page 50: ...ions 1 2 or 5 as selected 1 The center display shows d d divisions 2 The left display shows choices of 1 2 or 5 3 Press Sample to change or Tare to accept and advance to next menu See Figure A 4 Figur...

Page 51: ...ON See Table A 1 1 The center display shows dot 2 Press Sample repeatedly to select decimal point position Refer to figure A 1 for values 3 Press Tare to accept setting and advance Figure A 6 illustra...

Page 52: ...A 4 APPENDIX A SERVICE MODES...

Page 53: ...ale will prompt you for the correct weights to be used based on it s capacity NOTE The following displays illustrate the weights to be used with a 3kg scale 1 Turn the scale on 2 Enter password 123456...

Page 54: ...ow center and right windows indicate 0 See Figure B 5 Figure B 5 Final Calibration Weight Display 11 Remove all calibration weights from the scale B 1 CALIBRATION Cont 9 Add the third weight to the to...

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Page 56: ...PN 80010584 B SERVICE MANUAL EC SERIES SCALES 80010584...