OHAUS 700 Series Field Service Manual

Contents

3-3CHAPTER 3 SERVICING3.2 SERVICE OF MODELS 310/311 HANGING PAN BALANCERefer to Figure 5-2 in Section 5 for identification of parts.A. Non-RepeatabilityProblem: Bent Damper VaneSolution: Straighten with fingers or needle nose pliers. (Note: Hold down Beamwhen performing this operation.)Problem: Foreign material on magnetsSolution: Remove with adhesive backed tape.Problem: Dull Knife EdgesSolution: To check, set Balance at zero, hold down Beam and release. Hold Beamup and release. If Balance does not return to zero, knife edge should be replaced.These parts are replaceable in the field but it is not recommended. Special tools arerequired to reassemble End Loop, and even though the Knife Edges can bereplaced in the field, the alignment technique is difficult without extensive training.B. Can Not Zero BalanceProblem: Zero Adjust Knob missing or Leaf Spring missing.Solution: Replace with new assembly. (Note: Hold down Leaf Spring until flare onKnob has passed over the spring. To perform this operation, Beam should beremoved from the balance.)Problem: Shot missing from Pan Support assemblySolution: Remove hanging assembly and place it upside down on desk or bench.Remove screws on Pan Support Assembly and all weights and shot. Re-hang Panand with Zero Knob set at mid point. Set all parts on the Pan (poise at Zero). Addor take away shot until Balance returns to zero. Then re-assemble. (Note: hangingPan Balances are adjusted with Pans and Balance Serial Numbers matched. Mixingup Pans will cause this problem. When replacing the removable Pan you will haveto go through this operation.)Problem: Dial-O-Gram ® balance Dial is out of calibration. Solution: This is a problemthat should be corrected by a trained technician.3.3 SERVICE OF 1200 SERIES SCHOOL BALANCERefer to Figure 5-3 in Section 5 for identification of parts.NOTE: Non-Removable Knife Edges, must replace Beam.Problem: Beam does not move.Solution: Check Beam Dampening Device. (Metal Loop that looks like a paper clipcoming out the left side of the Balance Base). Bend so it does not touch Beam whennot in use