the pistol grip. They can be replaced by simply removing the sin-
gle screw and the plate at the bottom of the pistol grip. Views of
the control panels for the 720 and 820-S instrument are shown in
Figure (1).
B) Operating Procedures:
1. Mechanical Adjustment
a) Loosen the knurled nut (720 only) on the telescoping
handle and extend the detection head to a comfortable
carrying position with the arm extended as shown in
Figure 2A
.
b) Keep the extension arm vertical and set the detection
head flat and as low to the ground or pavement as is
practical for sweeping the area.
2. Electronic Adjustment
a) First test the condition of the battery supply. Turn the
unit
“ON”
by turning the
SENSITIVITY/ON-OFF
control know clockwise unit until it clicks on. Now
push the
BATTERY TEST PUSH-BUTTON
and
observe the
METER
. A reading anywhere in the green
shows that the battery supply is
OK
.
b) With the unit
“ON”
and with the
DETECTION HEAD
away from any mental objects slowly turn the control
clockwise. For the first one-quarter of a turn there will
be no tone from the speaker and the meter will stay at
zero. As the control is advanced a full tone or signal
will be heard from the speaker. The meter needle will
move quickly to the full-scale position as the speaker
and meter always track together.
Model 720/820-S Valve Locators
3
