Thermal Arc ARCMASTER 300 MST Operating Manual page 54

d) Turning the VRD ON/OFF. (see Figure 14)
•
To turn VRD ON: rotate the trim potentiometer (VR1) on the display PCB fully clockwise.
When VRD is turned ON check that it operates as per VRD Specifications on page 46.
•
To turn VRD OFF: rotate the trim potentiometer (VR1) on the display PCB fully
counter-clockwise.
The VRD ON/OFF trim potentiometer MUST ONLY be positioned fully clockwise OR fully counter
clockwise as the VRD function will be unknown for every other position.
WARNING 10
Figure 14. VRD ON/OFF Step D
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