CHAPTER 2 DIAGNOSTIC GUIDEOhaus Corporation www.ohaus.com 2-2 Pioneer™ Balances Service Manual2.2.1 DiagnosisTABLE 2-1. DIAGNOSTIC GUIDESYMPTOM PROBABLE CAUSE REMEDYBalance will not turnon with AC adaptersuppliedMain power source is offAdapter defectiveInput connector at rear ofBalance may be defectiveMain PC Board defective.Check the main power source outlet forproper voltage.Check the AC adapter voltage outputwhich should match the specifiedvoltage on the adapter. If voltage islow or nonexistent, replace the ACadapter. If OK, proceed.Open the balance. Leave the cableconnected to the Top Housing.Reconnect the AC adapter. Check ACvoltage at the input connectorterminals. It should read 12 V AC. Ifvoltage is not present, replace the inputconnector. If OK, proceed.Replace the Main PC Board.Balance does notrespond to front panelcontrols.Main PC Board is defective Replace the Main PCB.Poor accuracy. Unstable environment.Balance out of calibration.Balance was not re-zeroedbefore weighing.Move balance to suitable location;ensure that balance is level.Calibrate the balance.Press >O/T< with no weight on the pan,then weigh item.Balance can be turnedon but will not calibratemanually.Incorrect weights.Balance not level.Balance is unstable.Load cell assemblydefective.PCB is defective.Verify that proper weights are used.Level the balance.Perform Automatic Internal Calibration.(See Appendix A.1.)Enter Service mode (Appendix B) andperform a Span Calibration. If this fails,check the InCal Weight Assembly andthe Load Cell Assembly. Ensure thatall parts are clean and properly aligned.Repair the Load Cell.(See Chapter 3.)Replace the PCB.
