Minelab GPX-4000 Quick Start Manual

Search
Mod

e

Soil

/

T

imings

Ground

B

alanc

e

Coil

/

Cance

lTrackin

g

Salt

D

eep

Patch

S

ensitiv

e

Fixed

Double D

M

N

G

Set the front panel switches to the following positions:

Threshold

Auto Tune

Ground
Balance

Tracking

Fixed

Threshold

On/Off

Hold for FP

Press the On/Off button on the rear control panel. (pg. 25)

Turn the Threshold control up until a tone is audible
through the headphones.

(pg. 34)

Raise the coil off the ground and Press the Auto Tune
button to reduce electrical interference. The tuning
process takes approximately 60 seconds. Do not move the
coil or pass metal objects near the coil during the tuning
process.

(pg. 33)

Whilst lowering and raising the coil between 25mm and
100mm (1" and 4") from the ground, change the Ground
Balance switch to Tracking. Any variations in the Threshold
will smooth out within 3-5 seconds.

(pg. 40)

Adjust the Threshold to a very faint but still audible level.
It should be smooth with only minor fluctuations.

(pg. 34)

You are now ready to start searching!

Quick Start

Search
Mode

Soil /
Timings

Ground
Balance

Coil /
Rx

Patch Sensitive Fixed Double D

NG

Minelab Electronics Pty Ltd

PO Box 537, Torrensville Plaza
Adelaide, South Australia, 5031

Australia

Tel: [phone]
Fax: [phone]
Email: [e-mail]

Minelab International Ltd

Laragh, Bandon
Co. Cork

Ireland

Tel: [phone]
Fax: [phone]
Email: [e-mail]

Minelab USA Inc

871 Grier Drive, Suite B1
Las Vegas, Nevada, 89119

USA

Tel: [phone]
Fax: [phone]
Email: [e-mail]

For further product information
and detecting tips, refer to:

WWW.MINELAB.COM

Minelab is always interested in your opinions.
If you have any questions or comments regarding
the GPX-4000 or any other Minelab product, please
feel free to contact us via your local Authorised
Minelab dealer, or write to us:

The World Leader in Metal Sensing Technology

From our origins in 1985, Minelab have specialised i n advanced electronics

technologies. O ur competitive advantage was created almost imm ediately with

a highly competent and innovative Rese arch and Development team, inspired by

the genius of Mr. Bruce Candy.

This commitment to innovation has enab led us to successfully market feature-

packed Consumer coin and treasure detecto rs enjoyed by hobbyists worldwide

as well as high quality gol d detectors used by both professionals and am ateurs.

Minelab’s advanced technology is also incorporated in detection equipment

designed for military and huma nitarian de-mining projects throu ghout the world.

Today Minelab has manufacturi ng, distribution and customer service op erations

in Australia, Europe and the United States, and is an ISO 90 01 Quality Endorsed

Company. ISO 9001 is a worldwide qualit y standard certification that ensures the

highest level of produc t quality for our customers.

Item Number: 4901 - 0060
Revision: 1.1

THIS DEVICE COMPLIES WITH
PART 15 OF THE FCC RULES

Operation is subject to the following two
conditions: (1) this device may not cause
harmful interference, and (2) this device
must accept any interference received,
including interference that may cause
undesired operation.

For Consumers within the European Union:
Do not dispose of this equipment in general
household waste.

The crossed out wheeled bin indicated
on this equipment is an indicator that
this unit should not be disposed of in
general household waste, but recycled
in compliance with local government
regulations or environmental requirements.

Please dispose of this equipment via a
recycling service or centre, or by returning
the unit to the respective Minelab or Halcro
outlet as appropriate for your unit. This will
enable the equipment to be disposed
of in an environmentally safe manner.

Disposal of unwanted electronic equipment
in landfi lled waste may contribute to
adverse long term environmental eff ect
due to the leaching of contaminating and
toxic substances contained within some
electronic equipment.

Working for a Clean er,
Greener Future

Disclaimer:

The Minelab metal detector discussed
in this operating manual has been
expressly designed and manufactured as
a quality hobbyist metal detector and is
recommended for use in coin, treasure and
general metal detection in non-hazardous
environments. This metal detector has not
been designed for use as a mine detector
or as a live munitions detection tool.

Please note:

Since there may be a variety of options
available for this detector, equipment
may vary according to the Model or
items ordered with your detector. Certain
descriptions and illustrations may also diff er
(in this manual) from the exact Model that
you purchased. In addition, Minelab
reserves the right to respond to ongoing
technical progress by introducing changes
in design, equipment and technical
features at any time.

©

Minelab Elect ronics Pty Ltd

This document contains proprietary

information w hich is protected by
copyright. Ap art from any use as pe rmitted
under the Copyr ight Act 1968, no part m ay
be reproduced b y any process without
written permission from Minelab Electronics
Pty Ltd, 118 Hayward Avenue, Torrensville,
SA 5031, Australia.

WARNING. This doc ument contains Minelab

Electroni cs Pty Ltd rights, te chnical data or
restricte d rights data, or both . Patents and
trademarks apply.

1

Gold detecting is a fascinating and rewarding
activity enjoyed by people all over the world. By
getting to know your GPX-4000 you can become
one of the many who find gold and valuable
treasure.

The GPX-4000 is Minelab's most advanced
gold detector. It is a high precision instrument
incorporating Multi-Period Sensing (MPS), Dual
Voltage Technology (DVT), and the latest in
high-tech analogue components combined with
advanced digital processing.

The GPX-40 00 will locate gold in all types of terrain,
especially highly mineralised ground conditions,
with greater efficiency than any previous detector.

This manual is designed to help both the beginner
and expert prospector get the best performance out
of the GPX-4000.

Minelab wishes you every success in your quest
for gold and treasure!

Congratulations on
Purchasing the Minelab
GPX-4000

2 3Contents

Quick Start Back Cover
Introducing the GPX-4000 4
List of Parts 6
Assembly 8
Adjusting the Detector for 16
Comfortable Detecting
Charging the Battery 18
Battery LED Patterns 20
Taking Care of Your Battery 21

Functions 46
Settings 47
Accessing Functions 48
Accessing Settings 49

Detecting Basics 22
Detector Sounds 23
Front Control Panel 24
Rear Control Panel 25
Turning the Detector On 26
LCD Menu Structure 27
Search Mode 28
Factor y Pres ets 30

Pinpointing / Locating the Target 70
Recovering the Target 72
Detecting Tips 74
Commande r Coils 76

Choosing the Right Coil for the Job 78

User Preferences 80

Tun e / Reducing Electrical Interference 32
Auto Tune 33
Threshold / Adjusting the Background Audio Level 34
Soil/Timings / Optimising for Soil & Target Types 36
Ground Balance / Reducing Ground Noise 38
Ground Balance Procedure for Tracking 40
Ground Balance Procedure for Fixed 42
Coil/R x / Changing Sensitivity & Rx Fields of the Coil 44

Function

Select

Setting

On/Off

Hold for FP

Auto Tune

Search
Mode

Soil /
Timings

Ground
Balance

Coil /
Rx

CancelTrackingSaltDeep

Patch Sensitive Fixed Double D

MNG

Threshold

Coil

Smart
Point

Troubleshooting 81
Glossary of Terms 82
Taking Care of Your Detector 85
Technical Specifications 86
Warranty 87
Service Repair Form 88

Volu me Limi t / Setting the Max Volume of all Sounds 50
Audio Tone / Adjusting the Pitch of the Threshold 52
Signal Peak / Adjusting Pitch Variation of Target Signals 53
Tracking Speed / Keeping up with Changing Ground 54
Sensitive / Soil/Timings 55
Ground Balance Type 56
Ground Balance Procedure for Specific 57
Iron Reject Off (All Metal) / Accepting All Target Types 58
Iron Reject / Rejecting Iron Targets 60
Battery Test / Viewing the Battery Voltage 62
Manual Tune / Reducing Electrical Interference 63
Audio Type / Changing the Response of Target Signals 64
Gain / Adjusting the Sensitivity of the Detector 65
Motion / Adjusting Sweep Speed 66
Response / Inverting the Pitch of the Target Signal 68

4 5Introducing

the GPX-4000

New Functions

Gain – The Gain function sets the overall sensitivity

level of your detector. In areas where conditions are
mild, you can increase the Gain. In areas that are
more dif ficult, Gain can be reduced.

Timings – The GPX-4000 features an improved
set of timings, increasing performance in different
conditions.

Ground Balance Type – In addition to Ground
Balance there is now the choice of two Ground
Balance Types, Normal and Specific. Specific Ground
Balance is designed to be used in very hot ground
and is especially useful with Monoloop coils.

Response – The Response function allows you to
invert the target response. Deep targets can now
sound like the more familiar, 'rising and falling' pitch
of a shallow target signal.

Motion – The speed at which you sweep the coil
has an effect on target response time and Ground
Balance adjustment. Matching your preferred coil
sweep speed with the corresponding Motion setting
can reduce noise.

The GPX-4000 utilises Minelab’s proven 'Dual
Voltage Technology' (DVT). This ensures an accurate
Ground Balance to provide maximum sensitivity and
depth in all ground types. The GPX-4000 can handle
heavily mineralised and salty ground conditions
with greater ease than previous detectors, which
effectively opens up NEW detecting areas.

The GPX-4000 offers three pre-programmed
Search Modes, set up for the three common search
techniques – Patch finding; General detecting and
Deep slow careful detecting. As you become familiar
with all the new functions of the GPX-4000, you can
then program your own settings for each Search
Mode.

All setting changes are automatically saved when
the detector is turned off and loaded when you
switch the detector back on. You can also restore the
Factory Preset settings at any time.

There is an LCD on the rear of the control box. Simply
scroll through the various functions of the detector
and adjust the setting. This is more accurate than
the old method of turning the control to ‘about 2­o’clock’. Now you can accurately compare the effect
of different settings and easily remember your
preferred levels.

6 7

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List of Parts

8 9

Attaching the Coil to the Lower Shaft:

1 Plug the two rubber washers into the holes on

either side of the lower shaft.

2 Ensure that the spring loaded pin of the lower

shaft is pointing downwards. Slide the lower shaft
into the bracket on top of the coil.

3 Insert the bolt through the lower shaft and the

bracket on top of the coil. Fasten with the nut
provided, being careful not to damage the thread
of the nut by over-tightening. This may need to
be loosened to adjust the coil to a comfortable
detecting angle.

The coil cable is directly wired into the coil and is not

removable. Any attempt to disconnect this cable will
void your warrant y.

If the coil becomes loose over time, the rubber

washers may need to be replaced.

Assembly

Attaching the Lower Shaft to the Upper Shaf t:

1 Rotate the twistlock of the upper shaft counter-

clockwise to ensure that it is loosened.

2 Compress the spring loaded pin of the lower shaft.

Slide the lower shaft into the upper shaft until
the pin reaches an adjustment hole. The pin will
spring out and clip into place.

Attaching the Handle to the Upper Shaft :

1 Slide the bungy cord clamp onto the upper shaft.

2 Slide the handle onto the upper shaft so that it

slopes away from you.

Attaching the Armrest to the Upper Shaft:

1 Place the two armrest halves on either side of the

upper shaft, aligning the armrest and upper shaft
holes.

2 Insert the bolts through the armrest and upper

shaft holes.

3 Loosely fasten the wing-nuts onto the bolts (these

will be tightened after the control box is attached).

spring loaded pin

10 11Assembly

Connecting t he Coil Cable:

1 Wind the coil cable around the lower and upper

shafts enough times to take up the slack. Leave
enough slack at the bottom of the cable near the
coil to allow the angle of the coil to be adjusted
while detecting.

2 Use the Velcro straps to keep the coil cable in

place against the shaft.

3 Plug the coil connector into the coil socket on the

control box, firmly tightening the retaining ring to
hold it in place.

Attaching the Armrest Strap to the Armrest :

1 Press both strap studs onto the armrest studs.

2 Push the armrest straps through the slots in the

armrest cover and then push the cover over the
armrest.

Connecting the Control Box to the Upper Shaft :

1 Place the detector on a flat surface, with the

handle facing upwards.

2 Position the armrest on top of the control box.

3 Clip the control box onto the armrest, ensuring

that the battery plug faces the rear.

4 Fasten with the wing-nuts.

5 Wind the Quick-Trak button cable around the

upper shaft and plug it into the Smart Point
socket in the control box. Ensure that the cable is
wrapped firmly, but avoid strain on the connector.

If the Quick-Trak cable

becomes loose, try securing
it onto the shaft with
electrical tape.

Always ensure that the control box is turned
off before connecting or disconnecting the coil
to avoid damage to the detector's electronics.

12 13

Attaching the Waistbelt to the Batter y Harness:

1 Place the belt on a flat surface with the studs

facing up. Ensure that all the studs are unclipped.

2 Place the harness on top of the belt, with the

battery pouch facing up. Press the belt studs over
the harness strap to hold the belt in place.

3 Turn the harness and waistbelt over so that the

pouch faces downwards.

4 Clip the shoulder strap buckles together.

Connecting the Battery Pack:

1 Place the battery into the battery harness pouch.

2 Connect the headphones and the power cable to

the appropriate sockets in the battery.

Assembly

#LIPTOGETHER

4URNOVER

Note: The illustration shows
the battery oriented for a user
holding the detec tor with their
left hand.

14 15Assembly

Fitting the Battery Harness:

1 Thread your arms through the harness,

so the battery pack sits on your back.

2 Clip the waist and chest buckles together.

Adjusting the Detector for Comfortable

Detecting, pg. 16.

Attaching the Bungy Cord:

1 Create a loop in the bungy cord.

2 Undo the plastic wing-nut and remove

the bolt from the clamp.

3 Push the bolt back through the clamp and

loop to secure the bungy cord to the shaft.

4 Fasten the screw with the wing-nut.

5 Clip the bungy cord onto one of the harness

shoulder strap rings.

Adjusting the Detector for Comfortable

Detecting, pg. 16.

16 17

For comfortable, long term
detecting, it is important
that you take the time
to adjust the detector
correctly.

Adjusting the Detector
for Comfortable Detecting

Adjusting the Batter y Harness:

A comfortable fitting of the battery harness will
ensure the longest detecting session possible,
without fatigue.

Ideally, the battery should be placed on your back so
that it counter-balances the weight of the detector.
You should be able to reach the switches of the
detector without putting excess strain on the bungy
cord.

Pull the straps outwards and downwards to tighten.
Push the straps back through the buckle to loosen.

Adjusting the Bungy Cord Clamp
(Bow Knuckle):

The correct position of the bungy cord clamp (bow
knuckle) along the shaft can help take the weight of
the coil.

Loosen the clamp screw so it can slide along
the shaft. Slide it to a position that feels most
comfortable for you.

You may need to change the length of the bungy cord
or the position of the bungy cord clamp when you
change coils or d etect on sloping ground .

Holding the Detector:

Thread your arm through the armrest and strap.
Grasp the handle of the detector and rest your
forearm in the armrest.

Adjusting the Position of the Handle:

Your elbow should sit just above the back of the
armrest and you should comfortably grip the handle.

Slide the handle into position. Using a screwdriver,
tighten the two screws to hold the handle onto the
shaft. Adjust the strap on the handle for your own
comfort.

Adjusting the Length of the Lower Shaft:

The correct length of the lower shaft should allow
you to swing the coil in front of your body without
any uncomfortable stretching or stooping.

If the coil is too far from your body it will be difficult
to balance and manoeuvre while detecting.

If the coil is too close to your body it may detect your
pick, the battery or any other metal which you are
carrying, causing confusing sounds.

Rotate the twistlocks of the shafts counter-clockwise
to ensure that they are loosened.

Compress the spring pins of the shafts and move
them up or down to suit. Once all shafts are clipped
into position, rotate twistlocks clockwise onto the
shafts until they are firmly clamped.

Caution: Some operators
may find it more
comfortable to fit the
battery around the waist.
This is fine, but just make
sure that the detec tor isn't
producing a signal from the
battery. If using a large coil,
have the battery as high up
on your back as p ractical
and comfortable to avoid
any unwanted interference.

18 19

The aluminium battery case contains the 7.4V
Lithium Ion battery pack and an internal charging
circuit. Supplied with the GPX-4000 is a mains
charger adaptor and a 12V vehicle charger adaptor.

When fully charged, the battery will provide enough
power to operate the detector for 12+ hrs.

The charger will recharge a flat battery in
approximately 4 hours. Partially discharged batteries
will require a shorter period of time to recharge.
There is no need to fully discharge the Li-Ion battery
before recharging. The batter y may be recharged at
any time when not detecting.

Vehicle Charger Adaptor

The vehicle charger adaptor will charge the battery
from the accessories socket (cigarette lighter) of
most motor vehicles. The socket must be 12-24VDC.

To prevent damage to the battery, do not start the
vehicle while the battery is connected.

Make sure your vehicle battery is in good cond ition
and charged before using it to charge the GPX-4000
battery.

To Charge with the Vehicle Charger Adaptor:

1 Disconnect the power cable from the battery.

2 Connect the vehicle charger adaptor to the

battery and to the vehicle accessories socket.

The colour scheme of the tri-colour LED will

indicate the status of the charging process.

(pg. 20)

Don't leave the battery on charge in a closed vehicle
on a hot day as it is temperature protected and will
stop charging.

Charging the Battery

A spare battery is available
as an accessory. If travel ling
into remote areas, a spare
batter y will ensure you can
continue detecting for long
periods of time.

Mains Charger Adaptor

The mains charger adaptor will charge the battery
from local mains (AC) power outlets.

To Charge with the Mains Charger Adaptor:

1 Disconnect the power cable from the battery.

2 Connect the mains charger adaptor to the

battery power plug and the wall socket.

3 Switch the wall socket on.

The colour scheme of the tri-colour LED will

indicate the status of the charging process.

(pg. 20)

20 21

The Lithium Ion battery is specif ically designed
for the GPX-4000.

The Lithium Ion battery is not compatible with
previous detectors and for this reason it is supplied
with a power lead with non-compatible plugs.

• Do not charge the battery at temperatures above 45°C (113°C).

• Do not charge the battery at temperatures below 0°C (32°F).

• Do not leave the battery in hot conditions (e.g. on the dashboard

of your car or rear parcel shelf).

• Do not immerse the battery in any liquid or allow water ingress.

• Do not to throw the battery or impact it in any way.

• Do not short-circuit the battery.

• Do not use the battery if it is damaged or deformed.

• Do not disassemble or reconstruct the battery.

• Do not incinerate the battery.

Return the battery to a Minelab authorised service centre for repair.
The use of non-approved components will VOID YOUR WARR ANTY.
There are no user serviceable parts within this battery pack.

Battery LED Patterns

Brief cycling red-orange-green: Occurs once (or a few times) when

the detector is turned on or when
a new battery is connected

Very brief orange blink: Beginning of charge

Solid orange: First phase of charge

Orange with green blink: Last phase of charge

Solid green: Battery is charged

Slow orange blinking: The battery has not been used for a long

time and its voltage has dropped below the
minimum charge. When the voltage increases
the routine battery charge will commence.

Slow red blinking: The battery is too hot. It has reached a

temperature over 60°C and will not charge.
Disconnect the battery and wait for it to
cool below 40°C in a cool place before
reconnecting.

Continuous orange blinking: The battery has been on charge for too long

and will no longer charge. Contact your dealer.

Rapid red-orange blinking: Output paused while the input voltage

is too low.

Solid red: There is a fault with the battery.

Disconnect and reconnect the battery.
If the LED is still red, contact your dealer.

Routine

Exceptions

Taking Care
of Your Battery

22 23Detector Sounds

Threshold (Background sound)

This is the background sound produced by the
detector. When a target is detected, the Threshold
changes in volume and pitch. Listen to the Threshold
carefully. Concentration is an important part of
detecting. A very deep or small target may only give
a minor change to the Threshold.

(pg. 34)

Target Response (Metal Object Response)

This is a change in the tone (pitch) and volume of
the Threshold when a target is detected and not
discriminated (rejected).

Electrical Interference

The detector may also produce sounds when not
over the ground. These will not be target signals, but
signals caused from the surrounding environment.
The GPX-4000 has a Tune function to overcome
electrical interference. (pg. 32)

Ground Noise

The detector may also produce various random
signals caused by different minerals in the ground,
sometimes referred to as false signals. The GPX­4000 has an automatic Ground Balance function to
overcome ground noise. (pg. 38)

Blanking

When sweeping over a rejected target, the Threshold
‘blanks’ (becomes silent) indicating that a target is
located underneath the coil, but has been rejected.
Blanking is a useful way of distinguishing between
desired and undesired targets. (pg. 59)

Low Battery

When the battery is low, a series of alarm signal
pulses are given at 1 minute intervals.

(pg. 62)

Tar ge ts

Buried metal objects are
referred to as targets.
Targets are comprised of
both ferrous and non­ferrous metals.

The GPX-4000 is a ‘motion’
detector. This means it
must be moving over a
target to detect it.

Detecting Basics

The GPX-4000 will perform at its best when the coil
is kept close and parallel to the ground at all times.
This will increase detection depth and response to
small objects.

Practise sweeping the coil over the ground in a
side-to-side motion, while walking forward slowly at
the end of each sweep. Slightly overlap the previous
sweep to ensure full ground coverage. An average
sweep speed is four seconds from left to right to left.

A variation in coil height at the end of each swing
may cause confusing sounds and reduce detection
depth, so an even, flat sweep is desirable.

When using a Monoloop coil, more overlap is required
to ensure that targets at maximum depth are not
overlooked.

24 25

Auto Tune

Search
Mode

Soil /
Timings

Ground
Balance

Coil /
Rx

CancelTrackingSaltDeep

Patch Sensitive Fixed Double D

MNG

Threshold

Coil

Smart

Point

Search Mode

Each Mode has
factory preset
settings to suit that
style of searching.
Search Modes can
also be customised
to suit different
detecting conditions.

(pg. 28)

Soil/Timings allows
you to change the
electronic pulses/
timings of the
detector to optimise
performance for
different soils and
target types.

(pg. 36)

Ground Balance

reduces the
effect caused by
mineralisation
in the ground.

(pg. 38)

Coil/R x allows
you to change the
sensitivity and
receive (Rx) fields
of the coil.

(pg. 44)

Auto Tune automatically reduces
electrical interference.

(pg. 33)

Coil Conne ctor

Connects the coil to the control box.

Smart Point is a connection point
for the Quick-Trak button, located on
the handle. Minelab also uses this as a
test port to ensure that your detector
is operating at peak performance
before it leaves the factory.

Threshold is the constant background
audio produced by the detector. This
control increases / decreases the level
of the Threshold.

(pg. 34)

Front Control Panel Rear Control Panel

Function

Select

Setting

On/Off

Hold for FP

Once a function
has been selected,
Setting allows you
to adjust its value.

(pg. 47)

Function Select

scrolls up or down
through the list
of functions.

(pg. 46)

LCD
(Liquid Crystal Display)

Displays all the menu
functions and settings.

Battery Connector

connects the control
box to the battery
and headphones.

On / Off

turns the detector
on and allows you
to restore Factory
Presets.

(pg. 26)