Product Manual
The ML-1 does not have a Low Battery Indicator, so an indication 
of this condition is “screaming” or not working at all. If this is the 
case, replace the batteries as explained below.
The ML-1M produces a “flashing” battery icon in the lower right 
corner of the LCD when the batteries are getting low. You don’t 
have to change batteries at this time; it is just an indication that 
only about 5% of battery life is left. Just be sure to have a spare 
set with you in the carrying case. Then, replace as stated below 
upon “screaming” or not working at all.
Note: Always remove both 9-volt batteries and discard properly 
before inserting any new batteries.
1. Upon removal of the old batteries and proper disposal, insert 
one new 9-volt battery at a time. The contacts are spring loaded 
for durability and ease of battery change. Insert the batteries 
properly, look for the “+” and “- ” markings in the battery box and 
insert the batteries accordingly. Ensure the polarity is correct 
because batteries can be installed backwards.
2. Once the second battery is installed, check immediately for 
correct operation of the instrument. If it does not operate, either 
the batteries are in backwards or the batteries are dead. Pull out 
and reset the batteries in the proper polarity and check for opera-
tion again.
3. Once operation is verified, replace the battery box cover.
The Captured Screw in the battery box cover can 
be turned with a 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.
upon “screaming” or not working at all.
Note: Always remove both 9-volt batteries and discard properly 
before inserting any new batteries.
1. Upon removal of the old batteries and proper disposal, insert 
one new 9-volt battery at a time. The contacts are spring loaded 
for durability and ease of battery change. Insert the batteries 
properly, look for the “+” and “- ” markings in the battery box and 
insert the batteries accordingly. Ensure the polarity is correct 
because batteries can be installed backwards.
2. Once the second battery is installed, check immediately for 
correct operation of the instrument. If it does not operate, either 
the batteries are in backwards or the batteries are dead. Pull out 
and reset the batteries in the proper polarity and check for opera
-
tion again.
3. Once operation is verified, replace the battery box cover.
The Captured Screw in the battery box cover can 
be turned with a 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.
SEARCH OR SURVEY WITH THE ML-1
When searching for a target, walk slowly, sweeping the 
locator back and forth in front of you. If your target is small 
or very deep, use a higher GAIN setting and walk slower 
sweeping the locator from side to side slowly.
Normally, a medium setting and a little less than normal 
walking speed will do fine.
“PIN-POINTING” THE TARGET REPLACING THE BATTERIES
Upon locating the target using the “Search or Survey” 
method, you can detect the exact location of a target such 
as a surveyor’s “PK” or “MAG” nail, by following these steps:
1. Change the GAIN setting to the lowest setting that will still 
define the target. See GAIN above to change settings.
2. Bring the locator to a vertical position by simply allowing 
the locator to swing to vertical while you hold the handle 
loosely.
3. Move the locator back and forth in an “X” pattern over the 
target.
4. Move the “X” pattern until directly over the target by 
crossing the “X” at the position of the peak of the signal.
LOCATOR
OPERATION
7-YEAR WARRANTY
The ML-1 & Ml-1M are guaranteed to be free of defect in 
materials and workmanship for 7 years to the original 
end user/purchaser.
Only authorized SSI repair personnel can repair units. 
Abuse, battery acid and water damage are explicitly 
excluded from warranty.
SubSurface Instruments, 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 SubSurface Instruments. No other 
warranty is expressed or implied.
Note: Any metal objects on the operator such as watches pocket knives, large belt 
buckles and steel-toed boots will interfere if the locator is brought too close to 
these objects or is operated on the higher settings.
Power: Turn the locator on by 
pressing and releasing the 
ON/OFF/VOL button on the keypad. Feel 
the click?
Volume: To change the VOLUME, press and hold the 
ON/OFF/VOL button and the unit will repeat volume cycles 
from the current setting. Just release the button at the 
desired VOLUME.
Gain: To change the GAIN (sensitivity) settings, repeatedly 
press the GAIN   button to “decrease” sensitivity and 
repeatedly press the GAIN button to “increase” the sensi-
tivity setting. Do this by one click at a time. (Each click of the 
button changes the setting up or down by one increment out 
of eight possible settings).
3. Once operation is verified, replace the battery box cover.
The Captured Screw in the battery box cover can 
be turned with a coin. Carefully align the 


