620LK Operation and Maintenance Manual – Rev. J – Updated January 2020
Page 9
13231 Rooster Springs Rd.
Austin, TX 78737
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(512) 858-4045
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info@amptec.com
amptec.com
D-2.3 Main Power Switch
To turn the unit on, the unit’s main power switch must be pressed for 2 seconds. This
momentary hold down routine was designed to prevent accidental power on while the
product is in its carrying case. When the power switch is first pressed and held, the
instrument’s LCD display should light up, as well as a small LED on the front panel,
indicating that the unit is now on. If the switch is pressed again, the unit will turn off. The
main power switch is covered with a silicon rubber boot to provide added water/dust
resistance. Under the rubber boot, there is a rubber o-ring for added weather
resistance.
The 620LK meter is set to automatically turn itself off after 5 minutes of no use in order
to preserve battery life. Contact AMPTEC if you would like to have this feature
deactivated.
D-2.4 Display and Backlight
The 620LK’s display backlight is yellow in color, and will light up when the unit is
powered on. As the 620LK’s display is LCD (liquid crystal display) and high quality, the
display itself should have a life lasting many years. Should the display become
damaged or stop operating properly, it can be replaced at an AMPTEC facility.
The unit’s autolock feature turns the meter’s backlight on and will freeze the reading
unless the “AUTO MEASURE RESET” button on the front panel is pressed or the meter
senses probe continuity is still established. Additionally, the display backlight is off while
the measurement portion of its cycle is active.
D-2.5 Resistance Range
The 620LK can make measurements from 0.00 to 1999.9 m
Ω
.
The meter starts in Auto Range, but pressing the “AUTO
MEASURE RESET” button when the meter’s backlight is not on
allows the user to cycle through the Auto, 200
mΩ, and 2 Ω
ranges.
If a measurement is made that results in the unit being over-
range, the display will indicate this with “>>> OR” and “1 - - - -“.
D-2.6 Low Battery Indicator
If the unit is running low on battery, the display will indicate this by showing “LO BAT” in
the top left corner. See section E-9.1 on page 17 for information on how to change the
instrument’s batteries.
D-2.7 Autolock Feature Information
The 620LK meter has a built-in autolock feature, in which the unit senses continuity was
established, and automatically samples readings and locks on the most accurate
resistance measurement.
