Minelab Eureka Gold User manual

The Minelab
Eureka Gold
INSTRUCTIONMANUAL
MINELA
B

WARNING
THISDOCUMENTCONTAINS
MINELAB ELECTRONICS PTYLTD
LIMITEDRIGHTSTECHNICALDATA, OR
RESTRICTED RIGHTS DATA, OR BOTH.
© Minelab Electronics Pty Ltd
This work is copyright. Apart from any use
as permitted under the Copyright Act 1968,
no part may be reproduced by any process
without written permission from
Minelab Electronics Pty Ltd,
118HaywardAvenue,
Torrensville SA 5031,Australia.
4901-0046-1.1 January 2003

Minelab Eureka Gold
Instruction Manual
CONTENTS
Page
1. Introduction.............................................................................4
2. List of Parts .............................................................................5
3. Assembling the Detector .......................................................6
3.1 Armrest/Upper Shaft Assembly .................................................6
3.2 Lower Shaft Assembly ..............................................................6
3.3 Completing the ShaftAssembly ................................................7
3.4 Shaft Mount ...............................................................................7
3.5 Rear Shaft Mount ......................................................................8
3.6 Hipmounting/Chestmount .........................................................9
4. Batteries ................................................................................10
4.1 Installationof NiMH Battery Pack ............................................10
4.2 InstallationofAlkaline Batteries ............................................... 11
4.3 Low Battery Warningand NiMH Recharging.............................12
4.4 Usingyour NiMH Chargers........................................................12
5. The Eureka Gold Controls ..................................................13
5.1 Volume Control........................................................................13
5.2 Threshold Control ..................................................................13
5.3 Sensitivity Control ..................................................................15
5.4 Frequency Switch ...................................................................16
5.5 Signal Switch ..........................................................................16
5.6 Balance Switch .......................................................................17
5.7 Mode Switch ...........................................................................17
5.8 Tone...........................................................................................18
5.9 Headphones..............................................................................18
5.9 Coils..........................................................................................19
The Minelab Eureka GoldPage 2

Page 4 The Minelab Eureka Gold
6. Quickstart Operating Instructions......................................20
6.1 BestSetup Positions.................................................................21
7. Detector Sounds ..................................................................22
8. Operating Instructions - Fundamentals .............................23
8.1 Operatingthe Eureka Gold........................................................23
8.2 GroundBalance.........................................................................24
9. Detecting Techniques..........................................................25
9.1 Sweeping...................................................................................26
9.2 PinpointingtheTarget................................................................27
9.3 DiggingtheTarget......................................................................28
9.4 AutomaticGround Balancing.....................................................29
10. Discrimination .......................................................................31
10.1 Discrimination of Iron Targerts ...............................................31
10.2 Discriminating in ‘Hot’ Ground ................................................31
10.1 Discriminating within Holes....................................................32
11. Prospecting Tips ..................................................................33
11.1 Mineralisationand ‘Hot’ Rocks ................................................33
11.2 Clay Domes ............................................................................34
11.3 Charcoal .................................................................................34
11.4 Gold Lore ................................................................................35
12. The Coil and Skidplate.........................................................36
13. Environmental Concerns.....................................................37
14. Care of the Detector ............................................................38
14.1 Trouble-shooting Guide ...........................................................40
15. Warranty and Service ...........................................................41
16. Specifications .......................................................................42
17. FCC Compliance and EC Conformity Notes ......................43
18. Minelab Service Repair Form .............................................44

Page 5 The Minelab Eureka Gold
1. Introduction
Congratulations on purchasing Minelab’s Eureka Gold prospecting
detector. The Eureka Gold can constantly and automatically adjust the
Ground Balance to keep it at the correct setting. This will ensure that the
detector is always operating to its optimum strength, reducing operator
fatigue and allowing more ground to be covered in a day’s detecting.
For sensitivity to a wide range of targets, the Eureka Gold has a choice of
three operating frequencies:
•6.4 kHz
•20 kHz
•60 kHz
Further refinements include target detection with pitch variation, better
signal-to-noise ratio in the electronics, and a 10” (25cm) Elliptical
Double ‘D’ coil as standard equipment.
This manual has been arranged with QuickStart instruction for
inexperienced users. More detailed notes about assembling the detector,
how its controls work and methods of detecting are also included and well
worth reading by all operators.
As always at Minelab Electronics, we strive to provide you with the best
metal detection equipment possible. With that in mind we present the
Eureka Gold - the best continuous wave prospecting detector available
today.
If you have any questions or comments we would like to hear from you.
Please contact your local authorised Minelab Dealer or write to us direct.
Since there may be a range of options available in this detector
type, equipment may vary according to the model or country of
issue. Certain descriptions and illustrations may differ (in this
manual) from the exact model that you have purchased. In
addition, Minelab reserve the right to respond to ongoing
technical progress by introducing changes in design, equipment
and technical features at any time.
We wish you every success in your prospecting and treasure hunting.

Page 6 The Minelab Eureka Gold
2. List of Parts
The box in which the Eureka Gold is shipped should contain the following
items. When you first receive your Eureka Gold check that all these items
are in the box:
•Eureka Gold Control Box
•10” (25cm) Elliptical Coil with Skidplate attached
•2-Piece Shaft Assembly including fibreglass lower shaft
•Aluminium 2-Piece Armrest (including nuts and bolts)
•Control Box Rear-mounting Bracket
•NiMHBatteryPack
•MainspowerNiMH Battery Charger
•NeopreneArmrest Cover
•2 Piece Armrest Strap
•Velcro Straps (2)
•Teardrop Washers
•Warranty Card
•UserManual
•Detector Stand
Pleaseentertherequireddetailsonyourwarrantycardandmailit toMinelab
ElectronicsPty Ltd. It is extremely importantthatwe receive your warranty
card within 14 days of date of purchase to register your new detector on
ourwarrantyfile.
The following accessories are also available to further improve your
detector:
• 12vNiMHBatteryVehicleCharger
• 11” Round Double ‘D’ Coil
• 15” Spider Double ‘D’Coil
• Hipmount Bag
• AlkalineBatterypack
• Padded Cordura Detector Transport Bag
• MinelabCap
• MinelabPoloshirt
• MinelabJacket

Page 7 The Minelab Eureka Gold
3. Assembling the Detector
Please follow these instructions to assemble the Eureka Gold. Refer to
the drawings to identify parts and how they are positioned. Please contact
your Minelab dealer for further instructions should any difficulties arise.
3.1 Armrest/Upper Shaft Assembly
a) Place the two armrest halves (4) on either
side of the upper shaft (2) and ensure that
the bolt hole is aligned.
b) Slide the nylon bolts through the bolt holes
and screw the nylon wing nuts (12) onto
the bolts with a couple of turns (do not
tighten).
c) Slide the detector stand (7) into the
runners of the armrest (4) and tighten the nylon wing nuts by hand.
d) Attach the armrest straps (6) using the press studs on both sides of
the armrest.
e) Push the armrest straps through the slots in the armrest cover (5) and
push the cover over the armrest.
3.2 Lower Shaft Assembly
a) Remove the tape on the lower fibreglass tube
(3) that is holding the black teardrop washers
(10) in place.
Note: Ensure the washers do not fall out after
removing the tape.
b) Remove the black nylon wing nut (12), and
bolt (11) from the coil (9).
Figure 2 -Armrest/Upper
Shaft Assembly
6
4
12
57
11
2
4
6
P0570-A
Figure 3 - The Coil and
Lower Shaft Assembly
10
9
11
P0588-A
19
3
12

Page 8 The Minelab Eureka Gold
c) With the teardrop washers in place, push the lower tube (3) into the
coil bracket so that the holes line up.
Note: Ensure that the black nylon spring clip near the top of the fibreglass
tube is pointing toward the rear of the coil.
d) Push the black nylon bolt (11) through the holes in the bracket on the
coil from the cable entry side, put on the spacer (19) and tighten the
wing nut (12) by hand.
3.3 Completing the Shaft Assembly
a) Slide the lower shaft assembly (3) into theAluminium upper shaft (2).
Note: The black plastic locking nut (18) may need to be loosened to
position the lower shaft assembly correctly.
b) Set the length of the shaft by locking the black nylon spring clip
into one of the holes provided, then tighten the plastic locking nut.
3.4 Shaft Mount
a)Positionthe control box sothattherecessinthe control box (1)isaligned
with the leading edge of the mounting clip (8). Push the
forward section of the control box upwards until the trigger ‘clicks’
indicating the control box is secured (see figure 5).
Figure 4 - Completing the ShaftAssembly
2
18
1
4
8
3
9
13
P0585-A

Page 9 The Minelab Eureka Gold
c) Connect the coil connector (13) to the plug on the rear of the control
box (14).
d) Use VelcroTM tabs to secure cable in the
correct position on the shaft maintaining
slack at coil and control box.
Note: Weather Protection - The hipmount
bag is designed so that it can be used to
weatherproof your control box while detecting in
inclement weather. The new design allows the
hipmount bag to protect the control box while still on the shaft. The
control box is positioned into the hipmount bag with the slot for the
mounting bracket positioned at the back. The velcroed panel is then
wrapped across the top of the stem. The hipmount bag is available from
your supplier as an accessory item.
3.5 Rear Shaft Mount
The Eureka Gold provides the option of mounting
the control box at the rear of the shaft (2),
beneath the armrest.
In order to mount the control box (1) in this
position:
a) Loosen the nylon wing nut from the armrest
and remove the detector stand.
b) Firmly wind between 17 and 20 turns of the cable around the shaft until
it reaches the control box.
Note: Leave enough slack at the bottom of the cable near the coil to adjust
the coil position without straining the coil cable.
Figure5 -Mounting the
Control Box on the Shaft
Figure6 -Mounting the
Control Box to the Rear
ofthe Shaft
8
2
1
P0573-A
P0572-A
13
8
14

Page 10 The Minelab Eureka Gold
e) Firmly wind the cable up the stem using the VelcroTM tabs to hold in
position.
f) Connectthecoilconnector (13) to the plug (14) on therearofthe control
box.
d) Clip the control box onto the rear mounting bracket (see figure 5).
b) Slide in the black plastic rear control box bracket (8).
c) Tighten the nylon wing nut on the armrest.
3.6 Hipmounting/Chestmount
Hipmounting is an alternative to mounting the detector on the shaft and
significantly reduces physical strain, enabling longer search time without
undue fatigue. A hipmount bag is available as an accessory item
for this purpose.
a) Check that there are charged batteries in the control box.
b) Place the control box into the hipmount bag with its control panel
facing outwards (see figure 7).
c) Place the hipmount bag in your preferred
working configuration. The hipmount bag can
be worn on the belt or over the shoulder.
Note: If mounting the hipmount bag on the chest,
a belt can be thread through the belt loop and
around the chest to hold the bag in position.
d) Wind about 5 turns of the cable around the
shaft. This will reduce the amount of excess
cable.
Figure7- Hipmounting
theControl Box
P0582-A

Page 11 The Minelab Eureka Gold
Note: Leave enough slack at the bottom of the
cable near the coil to adjust the coil position
without straining the coil cable.
e) Use VelcroTM tabs to secure the cable in
position at the base of the shaft and where
the cable leaves the shaft.
f) Take the excess loose coil cable and wind it
through the belt bracket of the hipmount bag
prior to connecting onto the control box
(see figure 8).
g)Connect the coil connector to the socket on the rear of the control box
and tighten the locking nut.
4. Batteries
Your Eureka Gold is supplied with a rechargeable 12 Volt NiMH battery
pack and mains charger. A car charger is also available as an accessory
item from your authorised Minelab Dealer.
4.1 Installation of NiMH Battery Pack
a) Ensure your NiMH pack is fully charged.
b) Place the base of the battery pack at the rear
of the battery compartment (A). Push the front
edge of the battery pack into position (B). The
two battery clips will “click” into position to hold
the battery pack in place (see figure 9).
Note: The NiMH battery pack is factory sealed
and does not open. Figure9 - Installing
the Battery Pack
Figure8- Hipmounting
theControl Box
B
AP0586-A

Page 12 The Minelab Eureka Gold
4.2 Installation of Alkaline Batteries
A 12 Volt battery pack to hold 8 ‘AA’ alkaline batteries is available as an
accessory item. These are useful to have as back-up if ever your NiMH
batteries are flat.
a) Ensure the detector is switched “Off” before opening the battery
compartment.
b) Slide open the lid on the battery pack.
c) Place 8 “AA” alkaline batteries (16) into the
base of the alkaline pack (15). Ensure they
are aligned as shown in figure 10 and as
indicated inside the compartment.
d) Slide the battery lid closed.
e)Place the base of the battery pack at the rear of the battery
compartment (A). Push the front edge of the battery pack firmly into
position (B). The two battery clips will “click” into position to securely
hold your battery pack in place (see figure 9).
Caution:Goodqualityalkaline batteries will power the Eureka for about10
to 15 hours and should always be used instead of standard carbon
batteries.Alkaline batteries should be removed from the detector if it is to
bestoredforextendedperiodsto avoiddamagecausedbyleakingbatteries.
Using headphones will extend battery life.
Figure10- Replacing
the Battery Lid
16
15

Page 13 The Minelab Eureka Gold
4.3 Low Battery Warning and NiMH Recharging
When the batteries are reaching the point at which they will no longer
operate, the Eureka Gold will emit a distinct sharp “pip” from the speaker,
approximately every 30 seconds. Shortly after this, the threshold will
increaseto aloudcontinuous signalthatcannot bereducedbythethreshold
control. When this tone is heard, it is recommended that the NiMH battery
packberecharged or alkaline batteries be replaced assoonaspossible to
avoidmissingany targets. The NiMH battery packcanbe recharged using
either the supplied mains powered charger or a 12V charger (available as
anaccessory)thatcan be plugged into the cigarette lighter ofyourvehicle.
Caution:Checkthemainschargervoltage. Only use the appropriate mains
charger for the country you are in.
4.4 Using your NiMH Chargers
Plug the charger into the socket on the rechargeable NiMH battery pack,
andplugthechargerintothepowersourceandswitchon.The carcharger
has a red light that indicates that it has power. Agreen light will appear on
the battery pack during charging. A completely flat battery will take
approximately 12-14 hours to fully charge. The green light on the battery
pack will fade/dim once it is fully charged. A fully charged NiMH pack will
givebetween15and 20 hours detecting time, depending on the numberof
targets found.
Figure11- Car and Mains BatteryChargers

Page 1 The Minelab Eureka Gold
5. The Eureka Gold Controls
This section gives detailed descriptions of the controls of the Eureka Gold
detectorandtheirfunctionality.Havingknowledgeofthesecontrolsmeans
that you will be able to achieve the best performance from your detector.
As you gain experience with your detector it may be useful to refer back to
this section.
The Control Panel of the Eureka Gold has been carefully designed,
especially the placement of the controls, so those you will need to use
most frequently are at your finger tips (see figure 12).
5.1 Volume Control
The Volume Control incorporates the On/Off switch. It is off when the
control is fully counter clockwise. Turn the Volume Control clockwise and
the Eureka Gold ‘clicks’ on.
This control sets a maximum limit on the loudness of the audio signal
obtained from various targets. If the Volume Control is close to the
maximum, the audio signal is proportional to the target signal level
(see figure 13). However, if the Volume Control is turned down, the audio
signal is the same for a smaller target, but limited for a bigger target.
Figure12 - TheEureka Gold ControlPanel

Page 2 The Minelab Eureka Gold
5.2 Threshold Control
The Threshold Control is used to set the continuous audio ‘hum’ or
‘threshold’ level. The Threshold Control should be set so the threshold
level is just audible, e.g. not too loud. Prolonged use at a loud level could
be irritating to the operator, and could mask a faint signal.
It is important to know that small targets or large but deep targets may not
produce a distinct audio signal, but rather cause only a slight deviation
from the threshold level. If the threshold level is set too high or too low, the
very small variations in audio signal which indicate very small or deep
targets can be missed (see figure 14).
Note: While detecting, the Threshold Control may require occasional
readjustment.
Therefore this control is a volume limiter. It is a useful feature when using
headphones, as audio signals which would otherwise be uncomfortably
loud can be limited while maintaining full response to small signals.
Figure13 - VolumeControl (The maximumaudio output (volume)can be limited)
Figure14 - ThresholdControlSettings

Page 3 The Minelab Eureka Gold
Inthegraphs(onpage13) the dotted line represents the level at which the
audio output becomes audible; signals cannot be heard if they are below
that dotted line. When the threshold is set correctly it is just above being
audible and even small variations in the sound level will be heard. If the
threshold level is set too high, then small variations in audio signal might
notbediscernible above the threshold level. If the thresholdlevelisset too
low there is no audible background audio signal and small target signals
will not go above the threshold of audibility.
5.3 Sensitivity Control
The Sensitivity Control affects the strength of all signals, small shallow
targets, large deep targets, mineralisation and other interferences. The
SensitivityControlalso affects the level of soundproducedby the detector
for a particular target. However, unlike the Volume Control, it affects both
small and large targets alike.
It is recommended that in most ground the Sensitivity Control should be
set to the maximum sensitivity. This is obtained by turning the control fully
clockwise.
Figure15 – SensitivityControl
(Theaudio outputis amplifiedaccording to the Sensitivity setting)
The Sensitivity Control should be decreased only in case of electrical
interference or poor ground conditions such as heavy mineralisation or
heavyironstone.The sensitivity should be decreased just enough tomake
the detector usable.

Page 4 The Minelab Eureka Gold
5.4 Frequency Switch
The Eureka Gold has three operating frequencies:
6.4kHz,20kHzand60kHz.Usually6.4kHzisbettersuited
to larger, deeper gold nuggets while 60kHz is better for
smaller nuggets near the surface. The 20kHz setting is
best for general purpose detecting, or a happy medium
between both these extremes.
After changing the frequency setting, there will be a period of 2 seconds
when the detector will not detect any targets. Also, it might be slightly out
of ground balance, but theAutomatic Ground Balance will quickly readjust
itself as you start sweeping the ground. If you want to make sure you don’t
miss any targets, you can ‘pump’ the detector as explained in the
Operating Instructions (see pages 23-25).
5.5 Signal Switch
TheSignalswitchprovides three levels ofaudioresponse:
Normal, Fine and Boost. In the Normal position, a target
signal is uneffected. A change in the pitch and volume
helps to separate target signals from the background
threshold tone.
IntheBoostposition, the targetsignalisamplified,offering
The Fine position is specially designed to enable the detection of small
and medium size targets close to the surface, especially in mineralised
ground.Itdoes this by amplifying andfilteringthe audio signal. This allows
the target signals to be amplified without amplifying the background
signals as occurs in boost mode. This mode may miss larger targets at
greater depths but will give greater sensitivity to smaller targets.
Excessive numbers of ‘hot rocks’ could make this mode undesirable in
some grounds.
extremedepth penetration in quiet soils orin an area with constant ground
mineralisation.Youarelikelytoencountersome spuriousnoiseif yousearch
in variable ground using the Boost setting. This mode is also useful to
pinpoint a target which gives a faint signal under normal circumstances.
Noisy (i.e. mineralised) ground will become even noisier if used in this
position. The signal will become even noisier if used in
conjunction with 60kHz.
P0216-B
P0217-B

Page 5 The Minelab Eureka Gold
5.6 Balance Switch
The Balance switch selects either Automatic Fast Track
or Automatic Slow Track, or the Fixed ground balance
position. In the two automatic positions the Eureka Gold
is an Automatic Ground Balance detector. This means
that the detector continually adjusts itself to maintain
ground balance, which will ensure that your detector is
Fast Track being the faster ground balance should be used where the
groundisheavilymineralisedorchangesrapidly. For ground which ismore
mild or reasonably constant in its mineralisation, use the slower
Slow Track.
It is important to know that a deep target may be ‘balanced’ out by
continual sweeping over it when pinpointing in the automatic modes. By
ground balancing next to the target then switching to the Fixed mode, the
target cannot be balanced out. For the same reason the Fixed mode is
recommended when locating targets once dug from the hole.
5.7 Mode Switch (Disciminate/All Metal)
The Discriminate switch allows the use of
the discriminator built into the Eureka Gold.
It has two positions: All Metal and
Discriminate. In the All Metal position, the
detector responds to all types of targets with
the same target response.
In the Discriminate position, the detector discriminates between ferrous
andnon-ferroustargets.Thediscriminatorgenerallyperformsbestonloud
signals. Its ability to Discriminate between ferrous and non-ferrous targets
may be affected by the depth and size of a target. Ferrous targets will be
signalled by a blanking of the audio threshold. Using the Eureka Gold
discriminating mode will not sacrifice sensitivity or depth, but it will not
necessarily discriminate to the full depth at which the target can be
detected.
searching to its greatest possible depth at all times. Fast Track causes
thegroundbalance to respond rapidly tochanginggroundconditions,while
the Slow Track setting responds at about half this rate.
P0580-A
P0221-C

Page 6 The Minelab Eureka Gold
5.7.1 DiscriminateControl
The Discriminate control sets the sensitivity to ferrous objects. At the
minimum setting small ferrous objects at shallow depths are less likely to
be discriminated, while at the maximum setting these objects are more
likely to be discriminated. Large ferrous objects should always be
discriminated unless they are too deep.
5.8 Tone
The Eureka Gold has a tone control which allows the
operatortoadjust the “tone” or “pitch” of theaudiothreshold
signal to suit the individual. Generally, this should be set to
the pitch that you find the easiest to listen to.
We would recommend that you experiment by testing on various targets
buried at different depths to find the tone that best suits your hearing.
5.9 Headphones
The headphone socket is located at the bottom right
corner of the front panel. Headphones used should be
of low impedance, but no less than 8 ohms. The socket
will accept most mono and stereo headphones with a
¼" jack.
When the headphone plug is inserted, the loudspeaker is automatically
disconnected so that sound only comes through the headphones.
When using headphones, you can adjust the Threshold control to a lower
threshold level, and outside noises, such as wind, will be less distracting.
Using headphones also conserves battery life. If the headphones have a
“Stereo/Mono” switch, set it to “Stereo”.
Headphones can significantly increase your chances of hearing a small
signal, therefore we recommend their use.
P0581-A

Page 7 The Minelab Eureka Gold
5.10 Coils
The Eureka Gold should only be used with coils that have been indicated
by Minelab Electronics as being suitable for use with this model.
The10”(25cm) coil supplied with the Eureka Gold is aDouble‘D’coil,that
is,itcontainstwo‘D’shaped windings which are partially overlapping. This
Double ‘D’ configuration is ideal for locating deep targets in variable
mineralised ground.
The Double ‘D’ detection pattern is “blade like” and is most sensitive from
its tip to its heal. This makes pinpointing targets easy, and allows more
ground to be searched with each sweep, as each sweep has to be
overlapped less.
In addition to the 10” (25cm) Elliptical Coil supplied with the Eureka Gold,
therearetwoother accessory coils available, the 11”Round and 15” Spider
Coils. Both coils will increase the depth of the Eureka Gold on larger
nuggets.
Lines indicate
areas of maximum
sensitivity
Double "D"
Profile of sensitivity
along Double coil
at various depths
"D"
P0587-A
Figure16 -Coil SearchPattern