4
Defender
™ Series Bases Service Manual
1.5
Tools and Test Equipment Required
1. Common hand tools
2. Standard electronics tool kit
3. Digital Voltmeter (DVM) capable of reading from 1 mv to 50 V dc.)
4. Megohmeter (50 Volt dc maximum test voltage)
5. Desk magnifier on a stand
6. Ohaus Indicator: Defender 5000, or equivalent commercial indicator
7. A calibrated Torque Wrench N.m.
– Ft/Lbs
1.6
Test Masses Required
The masses required to test the Ohaus Defender series Bases when connected to an Indicator must meet the
requirements of ASTM Class or OIML. Mass values 3kg to 600kg, depending on the Base model. The full
scale rated capacity of the Base should be used for Span calibration.
1.7
Service Strategy
The Load Cells used in Ohaus Bases are non-repairable. The repair method for the Base is direct replacement
of Load Cells with connecting cable and hardware.
The Defender series Base contains the following basic replaceable assemblies: Platform, Load Cell with
Connecting Cable, and Down Stop and mounting hardware. There is an exploded view drawing of the Base
and associated parts list in Chapter 5. This service manual contains sufficient information to isolate the
problem, replace the component, test and restore the Base to its original factory specifications.
1.8
Physical Description: Model Defender Series Base
Construction
Platform
– Stainless Steel
Scale Base
– Carbon Steel or Stainless steel
Load Cell
– Aluminum
Overloading
Corner Loading
–1/2 to 2/3 of Full Capacity
Safe Overload
– 150% of Full Capacity
Ultimate Overload
– 300% of Full Capacity
Operating Environment
Ambient temperature: -10º C to +40º C
Relative humidity: up to 80% at 31º C, decreasing linearity to 50% at
40º C
Height above sea level: Up to 2,000m
Operability is assured at ambient temperature -10º C to + 40º C
