OHAUS CKW-55 Service Manual

Also see for CKW-55: Instruction manual Installation and operation instructions Quick start guide

Contents

OHAUS CKW-55 Service Manual Manual pdf 27 page image

3-7CHAPTER 3 INDICATOR TESTING3.3 POWER SUPPLY TESTINGThe Power Supply Board is located in the Rear Housing. A replaceable fuse is located on the board. Thistest is made when the Indicator fails to turn on when the power source is on and the indicator is pluggedin.WARNINGHAZARDOUS VOLTAGES ARE PRESENT WITH THE INDICATOR HOUSING OPENED ANDAC POWER IS APPLIED, USE CARE WHEN MAKING ALL MEASUREMENTS.3.3.1 Voltage Measurements.NOTE: When the power cord is connected to the indicator, the Power Supply Board has power applied toit at all times.1. Disconnect power from the Indicator. (Remove the line cord plug from the power source.)2. Open the Front Housing, refer to procedure 4.1.3. Refer to Figure 3-4 and locate the fuse on the Power Board. Remove the protective cover andfuse. Check the fuse with an Ohmmeter. If defective, replace with a new fuse of the same type.Reinstall protective fuse cover and reconnect ac power and measure voltage at connector CN2.If voltage is not present, replace the Power Supply board. Refer to procedure 4.4.4. With a power cord connected to the power supply board, connector CN1 and measure thevoltage at connector CN2 that should be 12 V dc, +0.24 V dc. If 12 V dc is not present,continue. If 12 V dc is present, the Power Supply board is good.CAUTIONTHIS NEXT STEP CONTAINS ELECTRICAL HAZARDS, USE EXTREME CARE WHENMAKING MEASUREMENTS.5. Carefully measure the AC line voltage at the connector CN1 on the power supply. Check thatthe power cord is not intermittent and is operational. If the cord is defective, refer to section4.1 to open the housing and replace the cord. Disconnect the power cord from the powersource. If the power cord was not defective, continue with this procedure.Figure 3-4. Power Supply Location Diagram.. .