OHAUS NV212 Service Manual

Also see for Navigator NV1101: Instruction manual Instruction manual

Contents

OHAUS NV212 Service Manual Manual pdf 29 page image

CHAPTER 3 MAINTENANCE PROCEDURESNavigator Series Service Manual 23 Ohaus Corporation www.ohaus.com3.4 REPLACING THE PRINTED CIRCUIT BOARD AND DISPLAY1. Open the scale – see Section 3.2.2. Pick the PCB off its mounting pins and position the PCB upside-down so that the load cell wireconnection is easy to access.3. Disconnect the Load Cell cable from the PCB. The load cell connection is a five-wire cablethat is soldered directly to the PCB. Before disconnecting the cable record the wire colors andtheir location on the PCB. (Hint: A digital picture is an easy and reliable record.) Disconnectthe cable connecting the PCB to the Load Cell by un-soldering the 5 wires from the PCB.Take care not to over heat the PCB which will damage the thin PCB conductors.4. Unsolder the AC Cable wires from the PCB.5. Follow these steps in reverse order to install the new PCB.6. Configure the Scale. (See Appendix C.)Note: The PCB and the LCD Display are supplied as a single unit. However, if only the LCDDisplay needs replacement, it can be separated from the PCB by unsoldering the fine lead-wiresconnecting it to the PCB. When installing the new LCD Display, carefully feed the lead-wiresthrough their holes, check that the new assembly is seated properly on the PCB and then solder thelead-wires.3.5 REPLACING THE FUNCTION LABELThe Function Label may need to be replaced. (See Chapter 5 for parts information.) Use a broadblade, such as a wide X-Acto™ knife, to remove the label. Clean the glue residue from the Housingsurface. Then carefully place the new label where the old one was. (See Figure 3-8.)Figure 3-5. Function Label Removal3.6 DOWN-STOP ADJUSTMENTThe purpose of the down-stops is to protect the load cell from physical damage. The down-stops arecreated by contacting bosses in the Base and adjustment screws or bosses in the Sub-Pan. The NVmodels have 3 down-stops, left, right and center near the load cell attachment to the Sub-Pan. TheNVL and NVT models have 5 down-stops, left-front, left-rear, right-front, right-rear and center nearthe load cell attachment to the Sub-Pan.NV models with capacity greater than 2kg and NVL / NVT models with a capacity greater than 10kgdo not have adjustable down-stops. The down-stop bosses on the Sub-pan are designed to be atthe correct distance to protect these load cells. The smaller capacity load cells require the down-stop clearance to be decreased for proper load cell protection. Adjustment screws are placed in theSub-pan down-stop bosses to reduce the clearance, see figure 3-6.Function Label