CHAPTER 3 MAINTENANCE PROCEDURESOhaus Corporation www.ohaus.com 3-28 Pioneer Balance Service Manual3.3.17 Position Sensor PC Board Removal/Replacement/Adjustment - AnalyticalWhen the Position Sensor PC Board is defective and requires replacement, proceed as follows:1. Open the balance, and remove theLoad Cell.2. Un-solder the thermistor wiresand ribbon cable. (See Figure3-75.)3. Remove the two inset screwsholding the Position SensorBoard in place.4. Remove the Position SensorBoard, and install thereplacement. Insert thescrews previously removed.Figure 3-75. Position Sensor Board(Analytical).Tighten the screws finger-tight to allow adjustment in Step 9.5. Re-solder the wires. (See Figure 3-75.)6. Place the Load Cell in position and insert the screws finger-tight, to facilitate Step 9.7. Connect the cable from the Main PCB to the Position Sensor Board.8. Operate the balance with the Weighing Pan in its normal position, but with the TopHousing off. Power on using the middle button on the PCB.NOTE:The Position Sensor Board contains an Optical Sensor which must be positioned inthe Ratio Beam’s center of travel for the balance to function properly.9. Adjust the vertical position of thePosition Sensor Board: if it is too highor too low, the display indicates Error8.X. (See Figure 3-76.) Move theboard until the display indicates otherthan 8.X.10. Tighten the screws on the PositionSensor Board. (See Figure 3-76.)11. Insert and tighten the two remainingscrews to secure the Load Cell.Check again that an Error 8.X is notdisplayed. (If so, repeat Step 9.)12. Disconnect the power. Install theLoad Cell Cover and close thebalance.Figure 3-76. Adjust Position Sensor Boardvertically until Err8.X does not appear.3-wire Ribbon CableThermistor wiresare soldered onthe bottomInset Screws
