Johnson Level 40-6450 User Manual

GAIN

KEYPAD

BATT

ZERO

LCD Meter: fills with the strength of the detected
signal and indicates ‘polarity’ by a “+” or “-” sign display
in the top of the LCD.

Speaker: Loud & Clear. Reports the change in
detected signal, from low to high frequency as the
target is approached.

All switches are “click” switches (press & release)

Zero: Used to adjust the unit to allow for magnetic
anomalies such as a magnetic gradient in the soil. Be
sure you are not detecting a target when hitting the
“zero” button. Unit returns to normal tuning after being
turned OFF.

ON/OFF: Turn the unit “ON” or turn the unit “OFF”

Gain Up: Increase the ‘sensitivity’. 8 positions.

ON

OFF

GAIN

GAIN

Magnetic Locators

Model No. 40-6430, 40-6440

40-6450

INSTRUCTION MANUAL

Gain Down: Decrease the ‘sensitivity’. 8 positions.

Micro-Processor: Gain settings are stored in memory

for next use.

SEARCH OR SURVEY

Walk slowly, sweeping the locator back & forth in front of you. If
your target is small or very deep, use a higher GAIN setting and
walk slower, with a slower sweeping motion. Normally a
medium setting on the GAIN and a little less than normal
walking pace will do fine.

NOTE: Any ‘ferrous’ metal objects on your person, such as
watches, large belt buckles, and steel-toed shoes will interfere
if the locator is brought too close to them, or is operated on the
higher setting.

“PIN-POINTING” THE TARGET

Upon locating the target using the “Search or Survey” method, you
can detect the exact location of a target such as a “PK”, “MAG­Nail”, or other steel or iron target by following these steps:

1. Change the GAIN setting to the lowest setting that will still
define the target, by using the “GAIN UP” or “GAIN DOWN” button.

2. Bring the locator to a vertical position by simply allowing it to
swing vertical, while you hold the unit loosely.

3. Move the locator back & forth in such a fashion as to create an
imaginary “X” pattern over the target.

LOCATOR OPERATION

Turn the POWER on or off by pressing the “ON/OFF” button on
the keypad. (Feel the click?) There is no volume control. To
change the “GAIN” (sensitivity) settings, repeatedly press the
“GAIN UP” button to increase the sensitivity, and the “GAIN
DOWN” button to decrease the sensitivity.

Each “Click” of the “GAIN” button changes the sensitivity up or
down ONE increment at a time, out of 8 possible settings. A
micro-processor remembers the “GAIN settings, and when
turned back on, the locator returns to the last used setting
before it was turned off. Don’t know what GAIN setting you’re
on? Press the “GAIN DOWN” button several times (more than

7), to be sure that you are on the lowest setting. Then press the
“GAIN UP” button and count each click up to 7 (or vice versa
down from the highest setting.) If starting from the lowest
setting, 3 or 4 clicks up is a good setting to begin locating.
These locators have sensitivity settings that are more ‘linear’.
more ‘linear’. Beware of competitor models which take larger
non-linear ‘jumps’ between settings, which give the impression

4. Move the center of the imaginary “X” directly over the target by
positioning the crossing position of the “X” at the “Peak” of the
signal response.

REPLACING THE BATTERIES

(40-6430 & 40-6440 ONLY)

9V Alkaline Batteries

1. Unscrew the cap on top of the unit to expose holder end.

2. Pull the battery holder out by the tab so you can service it.

3. Remove the top half of the battery cover to expose batteries.

4. Replace all three 9V batteries with new ones & replace cover.

5. Slide the battery holder back into the tube, tab end out.

6. Replace the cap and properly discard old batteries.

7. Once operation is verified, replace the battery box cover.

6. Replace the cap to the ML-3 & properly discard old batteries.

The Captured Screw in the battery box cover can be turned with a

3. One operation is verified, replace the battery box cover.

coin. Carefully align the cover holding tabs on the opposite end of
the battery box, lower cover onto box and tighten screw. Do not

The Captured Screw in the battery box cover can be turned with a

over tighten.
coin. Carefully align the cover holding tabs on the opposite end of
the battery box, lower cover onto box and tighten screw. Do not
over tighten.

LIMITED LIFETIME WARRANTY

The 40-6430, 40-6440, 40-6450 are guaranteed to be free
of defect in materials and workmanship for an unlimited
period of time to the original end user/purchaser.

Abuse, battery acid and water damage are explicitly excluded
from warranty.

Johnson Level & Tool, it’s owners, employees and assigns
shall not be liable for any action, inaction, injury, property or
consequential damage sustained or expenses incurred from
the use or misuse of this product.

Liability under this warranty is absolutely limited to repair,
service or replacement of the instrument, at the sole
discretion of Johnson Level & Tool. No other warranty is
expressed or implied.