CHAPTER 3 MAINTENANCE PROCEDURESOhaus Corporation www.ohaus.com 3-10 Pioneer™ Balances Service Manual3.3.8 Load Cell Disassembly – Precision Balances8. Unsolder and remove the four wiresshown in Figure 3-24. The two wiresat the bottom connect to the lightsource. They must be re-soldered aspictured here: white on left, red onright. The two wires on the topconnect to the Temperature Sensor.Their positions are not important.11. Remove the three screws holding thePosition Sensor Board in place.(The two on the right have washers.The one on the left doesn’t.) Figure 3-24. Position Sensor Board.12. Gently set the Position Sensor Board aside – avoid putting stress on the 3-wireribbon cable, which is soldered to the Contact Board.13. If the Ratio Beam is to be removed, unsolder the 3-wire ribbon cable fromthe Contact Board. (See Figure 3-25.)Figure 3-25. Contact Board with ribbon cable. Figure 3-26. Fine wires connected to theContact Board, and affixed to Ratio Beam.14. Carefully pry the Contact Board offthe Load Cell frame, and tape it tothe Beam. Take care not tostress or break the fine wiresconnected to the Contact Board.If they are broken, the Ratio Beammust be replaced.Note: The fine wires are glued toa post on the Ratio Beam. (SeeFigure 3-27.) This same glueFigure 3-27. Contact Board taped to RatioBeam after removal from frame.provides insulation. If the wires are disconnected from the Ratio Beam, theinsulation may be damaged, causing a short circuit. If this happens, the Ratio Beammust be replaced.Screws holdingPosition Sensor BoardContactBoardglued toframeSolderpointsWires glued to poston Ratio Beam
