Ohaus pioneer service manual

Major components are shown. Block style Load Cells are repairable. However, if serious damage has occurred, it may be necessary to replace the Load Cell.

Load Cell Kits are available for replacement purposes for all Block Style model balances. Each kit is assembled and consists of metal base plate, a Load Cell, the InCal Weight Assembly mounted to the base plate, and a package of labels. Check the label on the balance and verify the capacity and model before ordering a new Load Cell kit. Remove the Top Housing. Remove the Load Cell Shield by grasping the sides and pulling upwards.

Remove the four screws and washers that secure Load Cell to the Bottom Housing. Disconnect the cable s. Install the replacement Load Cell using the four screws previously removed and connect the flexible cables. Press it firmly into place.

Follow the instructions in Appendix C for installing the Load Cell. Re-calibrate the balance following instructions in Appendix B, Service Calibration. Re-calibrate the balance following instructions in Appendix A, Standard Calibration. Check the performance of the balance using tests in Chapter 4.

When the defective part is reached, replace it as described. But note that the procedures are not meant to be stand-alone you must complete each step. The following steps require the Block Style Service Toolset.

Do not drop or hit the Load Cell. Serious damage to the Load Cell can make it necessary to replace the Load Cell. To test the internal calibration, proceed as follows: 1. Connect an RS cable and a computer to the balance. Follow instructions in Appendix C, Section C. If the weight does not move, replace the InCal Motor. If the operation is not smooth, replace the entire InCal Mechanism. Remove the balances Housing and Load Cell, as described in earlier sections. Motor Coupler. Install the Coupler supplied with the.

If the Coupler is not in the position shown, remove the screw and coupler, reposition as shown, and tighten the screw on the Motor Shaft. Motor Shaft in counterclockwise position. The Motor Shaft must be in the position shown in Figure Test the InCal Mechanism again, as described in Section 3.

If the test is successful, re-install the Load Cell. Open the balance and remove the Load Cell as described earlier. Mounting Screws holding InCal Mechanism. Slide the InCal Mechanism as shown to remove it. Rotate the InCal Motor shaft until the Weight is in the top position. Slide the new InCal Mechanism into position. Fasten it with the three screws previously removed, but do not fully tighten them yet. When the Weight Mechanism is properly aligned, tighten the three screws and re-check alignment.

Test the InCal Mechanism with software. Remove the three screws of the Position Sensor Assembly. Raise the Position Sensor Assembly, which is held by the magnetic field. Removing Position Sensor. Position Sensor Installation: 1. Mount the Position Sensor Assembly. Align it centrally on the Ratio Beam Pin, and fasten it with the three screws.

Note: The flange of the Position Sensor Assembly is pre-bent to ensure its precise positioning after screwing it on. Do not attempt to bend it straight! Ratio Beam Pin. Ratio Beam Pin Alignment. Solder the Flexible Ribbon Cable to the six contacts shown in Figure Base Plate Removal 1. Remove the Weigh Below Hook and Screw. Base Plate Removal. Note: At this point, other repairs may be made to the Load Cell. Load Cell Mounting Components. Base Plate Installation 1.

Make sure the mating surfaces on the Base plate and the Load Cell are clean. Position the Load Cell on the base and install the two mounting screws. Do not tighten them fully. Looking down at the top of the Load Cell, align it with the Base Plate. Now carefully tighten the two mounting screws and re-check alignment.

Load Cell Alignment to Base Plate. Remove the Load Cell from the Mounting Plate. See previous section. Unsolder the Temperature Sensor Board wires. Disconnect the Ratio Beam cable. Install new board, ensuring the slot in the board is inserted in the slot in the Load Cell. Remove the three screws that secure the Position Sensor to the Magnet. Lift it off, gently but firmly to overcome the magnetic resistance, but avoid breaking the soldered connections to the Load Cell PCB.

It could ruin the Load Cell. Remove the screw on the bottom edge of magnet that secures the Temperature Sensor. It has a very fine thermister extending into the hole between the three screws on the bottom of the Magnet. Removing Temperature Sensor.

Dont adjust screws around Temperature Sensor hole! Do not to stress the transparent Position Sensor cable or the wires holding the Temperature Sensor. If necessary, remove the Contact Board Cover. Note: If Contact Board has a cover, as in Figure , the cover holder remains after cover is removed. Contact Board Cover is removed by squeezing the plastic post.

Insert the Centering. Centering Pins Installed. Hold the Contact. Board to ensure the fine coil wires cannot tear off, then remove the Fastening Screw as shown in Figure Contact Board Location. Note: The screw changes Figure Contact Board with cover holder off. Carefully loosen and remove the nuts on the Ratio Beam while holding the screw.

Remove the screws, washers and nuts holding the InCal Weight Arm. Remove the aluminum sleeves. Remove the centering pins. Centering Pins removed. If a new Ratio Beam is being installed, remove the existing weights from the old Ratio Beam and install them on the replacement Ratio Beam.

Ratio Beam Weight Removal. Examine the Load Cell slotted areas to be sure all areas are clean and free of debris. Hold the Load Cell up to the light to see into the slotted areas.

If dust or dirt appears in any slotted area, use pressurized clean air normally used for cameras and gently blow out any dirt. Use extreme care. Critical area is shown in Figure Critical Area. Note: Do not remove the three screws under the magnet that surround the Temperature Sensor. See Figure , page Magnet Area. Inspect the slotted area on the. Ratio Beam in position, as shown in Figure The Centering Pin also helps to avoid stressing the internal flexures. If the internal flexures are stressed in the process of reassembly, the Load Cell may be ruined, and would then need to be replaced.

Carefully slide the InCal Weight Arm into position. Be sure the notch at the end of the Weight Arm aligns with the pin inserted in Step 7 on the previous page through the Ratio Beams screw holes..

Weight Arm must be lifted slightly to insert Centering Pin. Do not use tools in this step. Install the screws, washers and nuts for the InCal Weight Arm. Work gently, to avoid stressing the Load Cells internal flexures. After installing the screws, washers and nuts by hand, hold the screw head with a screw driver while tightening the nuts for the InCal Weight Arm. Insert the pin just removed into the hole below the one holding the first centering pin. Centering Pins. Install the screws, washers and nuts for the Ratio Beam.

After installing the screws, washers and nuts by hand, hold the screw head with a screw driver while tightening the nuts for the Ratio Beam. Remove the Centering Pins. They should fall out easily. Be very careful not to break the wires on the board. Note: The screw changes from the upper to the lower hole on the Contact Board before inserting it into the hole on the Load Cell frame.

When screwing in, first turn the self-tapping Cell Board Screw in a counterclockwise direction until the first screw thread engages and then tighten it.

Gently hold PCB in position while inserting and tightening the screw that secures it. Carefully position the Temperature Sensor under the Magnet, so the Temperature Sensor a very fine thermister that extends from the board goes into the hole between the three screws on the bottom of the Magnet. Insert the screw to secure the Temperature Sensor Board. Temperature Sensor extends into a hole in the Magnet Note: Do not adjust the screws around the Temperature Sensor hole.

Place the Position Sensor on the Magnet. It has a cavity allowing it to rest squarely, aligned with the screw holes. The Ratio Beam pin must be centered in the hole in the back.

The Load Cell must be completely reassembled and installed in the balance Housing. Apply power to the balance. Measure the voltage again. If the two voltage values either side of zero are not of the same magnitude, e. Maximum difference is 0. Before and after servicing the balance, an operational test and various performance tests should be made to confirm that the balance meets specifications.

Turn the balance on and allow it to warm up. After it reaches ambient temperature, allow it to run for at least one more hour before performing these tests. NOTE: Make sure the test area is free from drafts and that the balance rests on a level and vibration-free surface. The mass values are listed in Table Connect a functioning Power Adapter to the balance power receptacle located at the rear of the balance. Plug the Power Adapter into a suitable power source.

The balances model number appears next, followed by a software revision number. This is a Segment Display Test. Figure is a full display test. Accurate performance of the Pioneer balances is determined by a series of four performance tests. The displayed readings are compared with the tolerances listed in Tables and Tolerance values are expressed in counts. A one-count difference is shown in the last digit on the balance display.

NOTE: The following performance tests are used to evaluate balance operation before and after repairs. The balance must meet the requirements specified in each test as well as the specifications listed in Tables Before proceeding with the following tests, the balance should be warmed up for at least five minutes, and calibrated.

The Precision Test measures the Standard Deviation of a set of similar weight readings, which should match the specification for each model, listed in Tolerance Tables and Tare the balance. The reading on the display should be 0g. Select a mass weighing near the maximum capacity of the balance, and place it on the center of the Pan. Observe and record the reading. Remove the mass. The reading should return to 0g 1 count. Repeat this test three times.

The reading should be within 1 count of the reading recorded. If so, the balance passes the Precision Test. If the deviation for any set of readings using the same mass placed on the center of the Pan is greater than the tolerance listed in Table or , the balance does not meet the precision specification. Inspect and correct the following areas: 5. Check for mechanical obstructions. Any foreign object touching any part of the moving assemblies will cause a balance to fail the Precision Test.

Inspect and correct as necessary. Inspect and correct if necessary. See the next section. 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. Mass Locations. Place a mass weighing half of the balances capacity in the center of the Pan. Move the mass halfway to the rear of the Pan and note the reading.

Move the mass halfway between the center and the left edge of the Pan and note the reading. Repeat this test for the right and front edges and note the readings. Note any differences in the displayed weight reading at all positions. See Tables and for maximum allowable variance for each of the four positions. The balance is very sensitive and adjustments will be affected.

Reinstall the Pan. Plug the power cord into the balance and turn it on. Place a mass that weighs the balances full capacity on the center of the Pan. Move the mass to the front, back, left and right edges of the Pan. Note the displayed values. Correct any errors by turning Corner-load Adjusting screws as shown in Figures and Use a nut driver. Use small adjustments, no more than turn at time. Repeat Off-Center Load Test. Turn the balance OFF. Remove the Platform. Re-assemble the balance.

Adjustment Screw Holes. Turn in direction shown by arrows. For errors front to back turn both adjustments the same direction. For side to side errors turn in opposite directions. Off-Center Load Adjustment screw holes on Precision models. Use a 6mm nut driver. Repeat the Off-Center Load Test. Off-Center Load Adjustment screw holes on Analytical models. Use a few strokes with a round needle file exerting slight pressure.

Warning Do not file at the edge at the flexible bearing positions. On completion of the adjustments, clean the filing sites by removing the grindings with adhesive tape do not blow the grindings away! Using a Needle File to adjust Off 6. Correct any error by filing at one or two of the marked positions. Remove the Platform and re-assemble the balance. 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 of the capacity of the instrument. Wear gloves when handling the mass. Before starting a repeatability test, set up the instrument as follows: Set Up: Enter the menu and adjust and record the following settings: A.

Set the Filter level to medium or the center of its range. Do not turn it off. Set the instrument to display the same units as the performance specifications. Zero the instrument, if it does not read zero.

Using a test mass approximately half the capacity of the instrument, place the mass on the center of platform. Record the reading on the worksheet provided. Remove the mass from the platform. Repeat this test starting at Step 1 until you record a total of ten readings Fill in the worksheet Table with the ten 10 readings.

Add the ten readings and divide the total by 10 to find the Mean average. Calculate the Delta for each reading and record in the work sheet. Calculate the Delta x Delta for each reading and record in worksheet. Add the ten Delta x Delta values and divide by 9 Calculate the Standard Deviation by taking the square root of the result from Step 9.

If it still does not meet specifications, perform a service calibration, and try again. See Appendix B for Service Calibration. This test is used to determine the linearity of the unit throughout its operating range.

The displayed readings are compared with the tolerances listed in the specifications for the instrument. See Specifications Tables, Chapter 1. A one-count change is equal to the last digit shown on the scale display. The masses used to perform this test can be utility masses. Press ZERO to zero the display. Place the Reference Mass in the center of the pan and record the exact value all decimal places displayed.

Remove the Reference Mass and verify that the display returns to zero. If it does not, disregard the reading, press ZERO to re-zero the display, and repeat the process. Place a mass equal to of the full scale capacity on the platform and press ZERO. Add the Reference Mass to the center of the platform and record the value. Place a mass equal to of the full-scale capacity on the platform and press ZERO.

Calculate the weight differences between the readings as shown below. The maximum difference should be less than or equal to the Linearity specification for the instrument. See Specification Tables, Chapter 1.

The difference in the weights of the test mass should be within the tolerance in Table If the balance remains out of tolerance, the Load Cell may need to be repaired. The exploded view drawings are designed to identify the parts which can be serviced on the balance in the field. There are many Pioneer models that have the same parts. There are eight diagrams and parts lists, covering the full range of models, as follows: Precision Balances Section 5. 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. Span calibration sets the balance's weighing range, within pre-set limits, for zero and a weight value at or near the balance's capacity. Linearity calibration minimizes deviation between actual and displayed weights within the balance's weighing range. Three weight values are used: zero, a weight value in the middle of the balance's weighing range and a weight value at or near the balance's specified capacity.

If you begin calibration and realize calibration masses are not available, exit the menu. The balance will retain previously stored calibration data. See Table for specified masses for all Pioneer models. Calibration masses are available as accessories from any Ohaus dealer.

The specified mass weight flashes. Pressing No will toggle to alternate mass weight. Place the indicated weight in the center of the Pan. Busy flashes. After a few seconds Clear Pan flashes.

Remove the mass from the Pan. NOTE: If calibration fails, ensure that the test area is free from drafts and the surface the balance rests on is level and free of vibrations. Then try to calibrate again. If it continues to fail, there may be an internal problem. To resolve internal problems, follow procedures in Chapter 3. SPAN appears. Press No. Linear appears. Press Yes. Note: Be careful not to touch the scale or the table while calibration is in progress, as it will cause the process to fail.

Press Yes to select Ramp. Press No to advance to Span Calibration. The ramp display shows the percentage of use of the A to D circuit. The actual value is not as important as how it changes. It should increase as the weight on the balance is increased. The ramp display should remain constant without fluctuations. To view the Ramp value, press Yes. A number will appear and should be constant.

Place masses on the balance from minimum to maximum capacity. The reading will increase but should not fluctuate. The example at right is with no weight on the Pan. The reading will vary with other balances. To exit the ramp function, press No. The balance advances to the Span calibration menu.

Press Yes to perform Span Calibration. See next page. This is distinct from user level span calibration, which allows a user to adjust the zero and maximum setting within the range established by the service menu span setting.

NOTE: The balance should be perfectly level before attempting a span calibration. Use the balances leveling feet at the rear of the balance , together with the leveling bubble which is just to the right of the Display. When span calibration finishes, Linear appears. Press Yes, to proceed to Linear Calibration. To exit, press No and then Yes to end service calibration.

Press No twice, to bypass Ramp and Span calibration. When Linear appears, press Yes. The specified maximum weight flashes. Place the indicated weight on the center of the Pan. The specified middle weight flashes again. When calibration finishes, Done appears briefly. EndServ appears. If you have completed Service Calibration, press Yes. Otherwise, press No to cycle through the Service Menu again. To install a new Load Cell. To update the software in the balance. For diagnostics.

Insert the CD and run Setup. After installation, run the program Service Tool. The program has 5 tabs across the top of the screen. Click on the tab for the function you wish to perform. If the default settings for communication have been changed, click on settings and change the settings in the software to match.

Record the following information from the balance to be repaired: 1. Serial Number from the label on the back of the balance. Model Number from the label on the back of the balance. IDNR Number, just above the label on the back of the balance. Provide the information recorded above. After receiving the data file from Ohaus, continue with the following steps. Figure C Enter the path to the image file, or click the Change button to locate the file.

Click the Write Image File button. The software will indicate the download progress. When complete, disconnect the power from the back of the balance, then re-connect. Perform Service Calibrations see Appendix B. Follow the steps in Section to replace the defective load cell. Open the packet containing labels that was supplied with the replacement Load Cell. These labels each contain a model number followed by the IDNR number. Carefully select the label that matches exactly the model number of the balance.

Put the new label on the balance. Power the balance from an AC adapter. Connect the balance to your computer. Start the Pioneer Service Tool Software. Click on the tab labeled Replace Loadcell. Enter the IDNR number xxx. Click the Start button. Follow steps in Sections 3. Then connect the balance to your computer. Click on the tab labeled Replace PCB. Enter the Serial Number value from the label on the back of the balance. Click the Start button 7. Connect the Balance to your computer.

Click on the tab labeled Download Software. Enter the path to the file to download, or click the Change button to locate the file. Click on the Start Download button. When prompted, disconnect the power from the back of the balance, then re-connect.

The software will indicate the download process. Start the Pioneer Software Service Tool. Click on the tab labeled Diagnostics. The scales response will be shown in the box on the right. Note: This procedure is used to test that the Incal Weight s move s smoothly. Observe weight displayed on the balance. A fluctuating display value indicates the weight is not stable. To correct this symptom, follow the procedures in Section 3. Open navigation menu.

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Report this Document. Flag for inappropriate content. Download now. Related titles. Carousel Previous Carousel Next. Jump to Page. Search inside document. C-6 Ohaus Corporation www. Pioneer, Carat and Gold Series displays. Pioneer Display Indicators. Load Cell Assembly. COM 1 Connector. Join the points by filling the gap: Figure Soldering points J1 and J2. Main PC Board is defective Unstable environment.

Balance out of calibration. Balance was not re-zeroed before weighing. Balance can be turned on but will not calibrate manually. Incorrect weights.

Balance not level. Balance is unstable. Load cell assembly defective. PCB is defective. Repair the Load Cell. See Chapter 3. Replace the PCB. Calibration Motor is not working. Main PC board is defective. Preventive Maintenance Checklist 3. For a balance without a Draft Shield: Figure Groove in side panels door guide aligns with tab on Housing.

Precision Load Cell: Section 3. Disassembly of Precision Balances with Internal Calibration Precision balances that have InCal require additional disassembly procedures.

Precision Balance with InCal Mechanism. Screws holding Weight Lifters Figure Turn the Load Cell over, so the Weight Arm assembly is visible. Proper manner to grasp Load Cell when removing Weight Arm assembly. Cable connects to Position Sensor Board. Access the 3 screws to release Precision balance Load Cell from top center. Bent Flexure. Fine wires connected to the Contact Board, and affixed to Ratio Beam. Magnets must be clean. Mounting Screw Mounting Screws Figure Contact Board.

Screws securing Flexure Arms Figure InCal Weights Figure InCal Weight Covers removed. Screws holding Weight Lifters 7. Screws on Bottom Mounting Plate Figure Screws removed from Bottom Mounting Plate inserted finger-tight into the Hanger. Top Bracket Figure Top Flexure Arm Analytical. Bottom Flexure Arm Analytical. Hanger with two screws. Ratio Beam Flexures Figure The Vane removed. The Vane is secured by two screws.

Contact Board with 3-wire cable attached Figure Four screws secure the Magnet Half to the Ratio Beam. The Magnet Half, when removed, should be cleaned. Use a small screw to fasten the Contact Board to the Ratio Beam. Service Fixture is installed prior to installing Ratio Beam Flexures. Screw holding Contact Board Figure Solder points for white wires Figure Installing the Vane.

Screws from Bottom Mounting Plate inserted finger-tight into the Hanger. Insert shims between the Hanger and the Load Cell on both sides. Bottom Flexure Arm. Top Flexure Arm. InCal Motor. With the Incal Weight in upper-most Figure InCal Motor Removal. Motor Coupler Figure Install the Coupler supplied with the replacement motor, then rotate the Motor Shaft by hand until it is in a counter-clockwise position.

Correct Angle Screw Coupler Figure Removing the InCal Mechanism. Equal Spacing Adjust Spacing Figure InCal Mechanism Alignment. Centering InCal Weight. It must be centered in the slots of the Weight Arm. Unsolder 6 Contacts 3 Screws Figure Alignment Area Figure Install new board, ensuring the slot in the board is inserted in the slot in the Load Cell Frame.

Slot Mounting Screw Figure Position Sensor. Load Cell PCB. Insert the Centering Figure Contact Board with cover holder. Pins from the Service Toolset in the holes provided. Centering Pins Figure Centering pins.

Centering Pins installed Centering Pins installed Figure Hold the Contact Board to ensure the fine coil wires cannot tear off, then remove the Fastening Screw as shown in Figure Carefully loosen and remove the nuts on the Ratio Beam while holding the screw heads to prevent movement. This is very important! Loosening Ratio Beam Nuts. Ratio Beam Screws and Washers removed. Loosening InCal Weight Arm nuts. Weight Arm Screws and Washers removed. Figure illustrates the InCal Weight Arm removed.

InCal Weight Arm Figure InCal Weight Arm Removal. InCal Weight Arm removed. Aluminum Sleeves Aluminum Sleeves Figure Aluminum Sleeves removed. Carefully lift out the Ratio Beam. Removing the Ratio Beam. Remove the Aluminum Sleeves. Ratio Beam Removed. This completes the disassembly. Removing the Aluminum Sleeves. Ratio Beam Weights Figure Critical Area Figure Load Cell Critical Area.

Check and clean the Magnet area. To clean it, use a small wooden stick with double-sided tape to remove any debris. Inspect the slotted area on the Ratio Beam. Clean it if necessary. Ratio Beam Vane Slotted Area. Four Ratio Beam sleeves are larger than the four Weight Arm sleeves. Carefully place the Ratio Beam into position on the Load Cell. Do not install the screws yet. Replacing the Ratio Beam. Insert a Centering Pin to hold the Figure Positioning the Ratio Beam over the magnet right.

Centering Pin goes into first hole after upward bend in Ratio Beam. InCal Weight Arm before insertion. Inserting InCal Weight Arm. Proper method for tightening nuts while holding screw head stationary. Centering Pins Install the screws, washers and nuts for the Ratio Beam.

Centering pins in Ratio Beam. Tightening Ratio Beam nuts. It offers a high level of operating convenience and useful functions to make accurate measurements.

A unique LCD panel has a large 7 digit, 7 segment display which indicates the weight value of an item being measured and a 7 digit British Flag display 14 segments which spells out items selected in the submenus. In addition, the display contains English words to indicate the status of the balance. Arrow indicators in the display prompt the user as to what panel keys are to be pressed to initiate a change. Panel controls are clearly marked as to their function with large Tare buttons on either side of the front panel.

Operation and setup of the balance is straightforward and easy. The Explorer Balance is available in a variety of full scale capacities ranging from 62 grams to 8, grams with FineRangeTM range models available. Legal for Trade versions are available. An Aftermarket Department with trained instrument technicians is dedicated to provide you with the fastest service possible in the event your instrument requires servicing. To ensure you make full use of the possibilities offered by your Explorer balance, we advise you to read through these operating instructions very carefully.

Check the completeness of the delivery. The following accessories are part of the standard equipment of your new Explorer balance. Immediately inform your Ohaus dealer if you have complaints or parts are missing.

This packaging guarantees the best possible protection for the tranport of your instrument. These factors will affect displayed weight readings. Home Manual Balanza Ohaus Explorer.

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