Fisher Research Labs M-97 User manual

M-97
Operating Manual
Valve, Pedestal & Box Locator
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
TestEquipmentDepot.com

ABOUT YOUR M-97
Using ideas that you, our valued customers, have passed on to us, the
M-97 Valve and Box Locator stands as the new and improved addition
to our line of highly successful M-95 and M-96 Locators.
The M-97 is an all-metal metal detector that can search through
concrete and asphalt and was designed for finding buried or paved
over valves, boxes, or manhole covers, or any other concealed metallic
object. It also locates targets made of aluminum, brass and lead. Please
remember, like all Valve and Box Locators, the M-97 is a Metal Detector
which should not be used as a substitute for a Utility Line Tracer. Fisher
Research Laboratory manufactures a complete line of equipment for
Line Tracing (Pipe and Cable Tracing).
New to the M series is the ease with which the M-97 can be stored.
Just compact the lower stem, twist the search coil 90 degrees, and fold
the search coil flat. The M-97 fits easily into the optional carrying case.
In the Fisher tradition, the M-97 is affordable, tough, and simple to use
while providing maximum performance. A two year limited warranty
comes standard with the unit.
CONTENTS
About Your M-97.......................................................................pg. 2
Features.....................................................................................pg. 3
Setting Up ..................................................................................pg. 3
Controls .....................................................................................pg. 4
Using Headphones ...................................................................pg. 5
Tuning ........................................................................................pg. 5
Searching ..................................................................................pg. 6
Specifications ...........................................................................pg. 7
Warranty ........................................................................ Back Cover

3
• Two knobs and a pushbutton for simple operation
• Adjustable shaft with double locking stem
• Ground Effect Rejection VLF eliminates annoying or false signals
from wet ground foliage, pavement or mineralized ground
• High sensitivity for maximum penetration through soil, asphalt
or concrete
• Built-in Battery Test
• Pushbutton Tuning to quickly & easily maintain optimum sensitivity
• Ultra Slow Auto-Tune to stabilize ground tuning and minimize
frequency drift
• Identifies metallic objects by speaker sound and needle
movement
• Compact size for convenient storage
• Waterproof search coil
FEATURES
SETTING UP
The M-97 comes ready to use.
Extend the lower stem of the M-97 so that the search coil rests be-
tween 6 to 12 inches in front of your feet. Your arm should be straight
and relaxed with your grip held loosely.
Tighten the locking nut/compression nut at the bottom of the upper
stem.
When the proper length is selected, the excess cable should be wound
around the stem. This can be done by slightly loosening the locking nut
and turning the lower stem, or by removing the search coil and winding
the cable by hand. Be sure to leave some slack in the cable.
Check the batteries by turning the Mode control to Battery Test posi-
tion and turning the Ground control to any number. A reading between
80 and 100 indicates the batteries are OK.
*With the 11” coil you must slide the lower stem completely out of the
upper assembly for the M-97 to properly fit in the hard carrying case.
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
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4
CONTROLS
Meter
The meter of the M-97 serves
two purposes for the opera-
tion of the instrument. When
used in the battery test mode,
the meter gives a visual indi-
cation of the battery strength.
A reading between 80 – 100
is desirable. If the reading is
below 80, search depth and
accuracy can decrease.
Please change the batteries, if
necessary. (Note: The batteries must be inserted correctly for the M-97 to
operate. Match up the correct battery terminals with the markings on the
inside of the battery holder. Failure to do so will not damage the instrument,
however, the instrument will not function).
When searching with the M-97, the meter gives a visual indication to any
change occurring in the field of detection. This is primarily due to the coil
passing over or near a metal object, but can occur when the ground
mineral conditions change.
On/Off Ground Rejection Control
This control turns the M-97 on and off. It is used to electronically balance the
M-97 to compensate for the natural mineral content of the soil or ground
surface. When tuned properly, raising and lowering the search coil above
the ground will not cause a change in the meter reading or audio tone.
Mode Switch
This control is used to change the mode function of the Locator.
Battery Test
With the detector turned on, the Battery Test mode will indicate
battery strength. This is a no-load battery test.
Normal
This setting is used for the Turn On and Go mode. The Normal
Mode requires very little Ground Rejection adjustment.
High
This setting is used for increasing the sensitivity of the M-97,which also
increases the depth searching capabilities of the instrument.
Retune Button
When this button is depressed, the instrument will rebalance itself to the
instrument settings and prevailing ground conditions.
M-97 Control Panel

5
Using headphones (not included) improves battery life, and prevents
the sounds from bothering bystanders.
It also allows you to hear subtle changes in the sound more clearly,
particularly if searching in a noisy location. For safety reasons, do not
use headphones near traffic or where other dangers are present. This
device is to be used with interconnecting cables/headphone cables
shorter than three meters.
USING HEADPHONES
TUNING THE M-97
There are two methods to tune and balance the M-97. One method
is for quick and easy operation; the other will allow you fine tune the
detector for deeper searching and greater sensitivity.
Turn On and Go Method
Select an area that is free of metal near and under the search coil. Turn
on the M-97 by setting the Mode control to “Normal” and Ground control
to the position “5”. (Hint: If the M-97 is loud sounding when the instrument
is turned on, press and release the Retune Button to quiet the instrument).
Raise the search coil about 12 to 18 inches above the ground (dirt, con-
crete, asphalt, etc.), and press and release the Retune Button.
Lower the coil close to the ground. There should be little or no change
in the tone of the detector. If the M-97 changes tone when the coil is
lowered to the ground, there is either a metallic object near the coil that
is causing the instrument to respond, or the soil conditions are such that
the M-97 needs to be more precisely balanced.
Proceed with locating your targets.
Precision Tuning Method
(This method can be used for the “Normal” setting, and must be used
for the “High” setting).
Select an area that is free of metal near and under the search coil.
Turn on the M-97 by setting the Mode control to “Normal” and Ground
control to the position “5”. Raise the search coil about 12 to 18 inches
above the ground (dirt, concrete, asphalt, etc.), and press and release
the Retune Button. Note any change of sound. If there is no change, or
only a slight change, the M-97 is balanced and ready to search.
If the sounds changes: Sound increases – Slightly decrease the Ground
setting. Repeat above procedure. Sound decreases – Slightly increase
the Ground setting. Repeat above procedure.Repeat until no (or a
slight) change of sound occurs.

6
SEARCHING
It is a good idea to establish a methodic search pattern. Avoid swinging
the M-97 like a golf club, swing the detector side to side keeping the
search coil the same distance above the ground. Your sweep pattern
should be a slow, half-circle motion. If you are searching for a small
target, it is a good idea to overlap your sweeps.
When the detector’s search coil starts to pass over a metal object,
the sound will increase and the meter readings will increase. Depending
upon the size and depth of the target, the target may appear (respond)
to be larger than it should. To get a visual outline of the target, you need
to reduce the sensitive of the M-97 by raising the coil and passing over
the target. This can help establish the edges of the target.
Another method that will give a visual outline is to purposely detune
the M-97. Move the coil away from the target. Slowly bring the search
coil toward the target. As the sound increases, press and release the
Retune Button. Continue to move the coil toward and eventually over
the target. The sound and meter readings will be more responsive as the
search coil passes over the target. You may need to repeat this step
more times if the target is at a shallow depth. Be aware that you can
loose responsiveness of the target by over reducing the Tuning Control
(sensitivity) of the M-97.
To reset the M-97 back to the balanced settings, lift the search coil off
the ground, and away from any metallic objects and press and release
the Retune Button. The M-97 will automatically retune to the original,
balanced settings.
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
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7
SPECIFICATIONS
Subject to improvement or modification without notice.
Output Frequencies of search coil ........... 4.5 kHz
Sensitivity ............... 0.20 mv RMS for full scale
Sensitivity Adjustment Range..................... 12:1
Output Indication . Meter 1 milliamp, ...... 0-100 linear scale
............................. Speaker ...................... 16-ohm impedance
............................. Headset (optional) ... 8-ohm impedance
............................. Audio Frequency....... 450 Hz
Power Supply +9V supplies: ....................... (2) 9V batteries
Battery Life Alkaline .................................... 15-25 hours
Power Consumption .................................. (-9V) 13.8 mA
................................. At min. sound 8 mA
................................. At max. sound 50 mA
................................. At Audio threshold 17.5 to 18.5 mA
Search Coil Configuration ......................... Double-D
Weight with 8-inch search coil ................. 3.3 lbs. (1.5kg)
11-inch search coil................. 3.9 lbs. (1.8kg)
Dimensions ............. 38 to 50 inches adjustable (96 to 127 cm)
Shipping Dimensions 6” x 13” x 35” (15.12 x 32.76 x 82.2 cm)
Fisher Research Laboratory does not warrant suitability to
specific use. Fisher Research Laboratory shall in no event
be liable for any direct, incidental, consequential or indirect
damages.
OPTIONAL ACCESSORIES:
Heaphones
Coil Covers
11” search coil
Hard carrying case
Vinyl carrying bag

8700004000 Rev2 011111
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
TestEquipmentDepot.com