Fisher M-66 User manual

M-66
Operating Manual
Valve and Box Locator
(Metal Detector)
FISHER RESEARCH LABORATORY

Description.............................................................................. pg. 3
Control Panel .......................................................................... pg. 4
Setting Up ............................................................................... pg. 5
Tuning ...................................................................................... pg. 5
Searching................................................................................. pg. 6
Specifications ......................................................................... pg. 7
CONTENTS

DESCRIPTION
1
3
The Model 66 Valve and Box Locator (M-66) offers the utility indus-
try an uncomplicated detector for finding buried metal objects.
This all-metal metal detector can even search through concrete
and asphalt. Please note that the M-66 is a Metal Detector which
should not be a substitute for a Utility Line Tracer. Fisher Research
Laboratory manufactures a complete line of equipment for Line
Tracing.

Meter The meter of the M-66 serves two purposes for
the operation of the machine. When used with
the battery test button, the meter gives a visual
indication of the battery strength. A reading
between 80 – 100 is desirable. If the reading is
below 80, search depth can decrease and accu-
racy may be in question.
When searching with the M-66, the meter gives a
visual indication to any change occurring in the
field of detection. This is primarily due to the
coil passing over a metal object, but can also
occur when the ground mineral conditions change.
Battery Test
With the detector turned on, depressing the
Battery Test button will indicate battery
strength.This is a no-load battery test.
On/Off Ground Rejection
This control turns the M-66 on and off. It is used
to electronically balance the M-66 to compensate
forthenaturalmineralcontentofthesoilorground
surface. When tuned properly, raising and lower
ing the search coil above the ground will not cause
a change in the meter reading or audio tone.
Tuning Control
This control is used to adjust the detector to the
thresh old point. This threshold point is a point
at which a very faint audio tone is heard and the
meter reads 10. The Tuning Control can also be
thought of as the Sensitivity control for the
M-66. 4
M-66 CONTROL PANEL
The M-66 Control Panel.

5
M-66 SETTING UP
The M-66 comes ready to use.
Extend the lower stem of the M-66 so that the
search coil rests between 6 to 12 inches in front
of your feet. Your arm should be straight and
relaxed with your grip held loosely.Tighten the
locking knot 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 knot
and turning the lower stem, or by removing the
search coil and winding the cable by hand. Be
sure to leave a some slack in the cable.
M-66 TUNING
Select an area that is free of metal near and un-
der the search coil.
Turn the M-66 on by setting the Ground control
to the position “5”. If the M-66 is sounding, turn
the Tuning control counter-clockwise until the
sound vanishes.
Check the batteries by pressing the Battery Test
button. A reading between 80 and 100 indicates
the batteries are OK.
Set the coil on the ground. Adjust the Tuning
Control (turn knob clockwise) so there is a slight
threshold sound, and the meter reads 10.
Lift the coil approximately 12 inches off the
ground.
Note any change of sound. If there is no change,
the M-66 is balanced and ready to search. If the
sounds changes:
Sound increases – Increase the Ground set
ting. Repeat above procedure.
Sound decreases – Decrease the Ground set
ting. Repeat above procedure.
Repeat until the no change of sound occurs.
Proper tuning is essential for accurate locating.

6
M-66 SEARCHING
It is a good idea to establish a methodic search pattern.
Avoid swinging the M-66 like a golf club, swing the detec-
tor 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 then
it should. To get a visual outline of the target, you need
to reduce the sensitive of the M-66. An easy way to do
that is to raise the coil and pass over the target. This can
help establish the edges of the target.
Another method that will give a visual outline is to reduce
the Tuning Control (sensitivity) of the M-66. Move the
coil away the target. Reduce the Tuning Control (turn
counter-clockwise) approximately ¼ of a turn. Sweep
across the target area. 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-66.

7
M-66 SPECIFICATIONS
Search Loop Configuration ... Double D (direct wired)
Output Frequency of Loop .... 4.5kHz,
Output Indication................... Speaker 16 ohm impedence
........................................... Audio fequency 450 Hz
Power Supply.......................... 9V, each
Power Consumption ............... (-9V) 17 mA
........................................... (+9V) 4mA min, 6 mA sound
........................................... threshold, 125 mA max sound
Weight with 8” coil ................. 4.25 lbs.
Operating Temp ..................... -40 to +1580F (-200to +700C)
........................................... search loop immersible in water
Dimensions ............................. Length 28” to 48” adjustable
........................................... (71cm to 122 cm)
Shipping Weight ..................... 7 lbs.
Shipping Dimensions ............. 34.75” x 12.75” x 5.25”
........................................... (88.3 x 32.4 x 13.3cm)
Subject to improvement or modification without notice.
Fisher Research Laboratory does not warrant suitability to specific use. Fisher
Research Laboratory shall in no event be liable for any direct, incidental, conse-
quential or indirect damages.

FISHER RESEARCH LABORATORY
200 W. Willmott Rd.,
Los Banos, CA 93635
Tel [phone] Fax [phone]
www.fisherlab.com email:[email protected]
EXPORT DEPARTMENT
P.O. Box 1896
New Haven, CT 06508 USA
Tel [phone] Fax [phone]
email:[email protected]
QUALITY
Fisher detectors are renowned for their quality.
Each detector is hand crafted in the USA with pride
PERFORMANCE
Ourdetectors andlocators aredurable, dependable,and
searchdeeper.
REPUTATION
Fisher produced the first patented metal detector in 1931. For
over 70 years, the Fisher logo has been a mark of excellence.
2 YEAR WARRANTY
Fisher believes in the products we produce and backs this belief
with a 2 year limited warranty. Warranty may vary outside the
United States. See your dealer for details
SERVICE
Fisher is committed to providing you, our valued customer, with
superior service. Each and every instrument is rigidly tested and
carefullyinspected duringassembly andbeforeshipment. Should
you have any questions or problems, contact:
FRL8700005