Service
PIranha OPERATOR INSTRUCTION MANUAL
CONGRATULATIONS!
Your new TESORO Metal Detector was designed to provide you with many happy hours of enjoyment in the most
rewarding hobby I can think of – treasure hunting. Ahead of you lie fascinating and exciting experiences as you step into the
past – uncovering artifacts lost by past generations. I wish we could share these experiences with you, and we wish you the
best of success.
Your TESORO Metal Detector is capable of meeting your needs in any conceivable treasure hunting situation. As with
any detector, operating skill and familiarity with this instrument are probably the limiting factors in determining how successful
you will be. We recommend that you read this manual and understand fully before attempting to use the instrument in the
field. As you become more familiar with your detector through practice, your rate of success will increase dramatically.
The TESORO Metal Detector is a precision electronic instrument, which will last for years if properly cared for. Treat it
right and it won't let you down.
Good Hunting! Jack Gifford
GENERAL DESCRIPTION
The PIranha is high performance metal detector which utilizes state of the art Pulse Induction technology and a
revolutionary new kind of Printed Spiral searchcoil. The PIranha will satisfy the requirements of the serious detectorist,
whether they are experienced or not, by incorporating simplicity and convertibility together. Don't be fooled by its simplicity,
the PIranha is capable of delivering peak performance by eliminating troublesome adjustments and complicated features
creating an extremely simple to operating light weight detector. The PIranha is the first of its kind. Not only does it offer a
totally new concept in searchcoil design making it more responsive to fine gold coins, jewelry, and nuggets, but it is also the
first to offer interchangeable searchcoils in a variety of sizes. The PIranha is packaged in an all new waterproof housing,
making it ideal for wet weather use, beach hunting, or diving in fresh or salt water. It is convertible to body/belt mount and
requires no special tools.
As a Pulse Induction instrument the PIranha will provide mineral free operation in virtually all ground mineral or salt water
environments. Equipped with auto tuning the PIranha is a motion based All Metal detector. Though the searchcoil must be
moving when pinpointing, due to the auto tuning, the amount of motion is so slight that pinpoint is easily accomplished.
Designed as a turn on and go all purpose detector, the PIranha requires no special ground adjustments or complicated
set up. A variety of optional searchcoils provides the operator greater versatility and a wider range of site selection. A guide to
selecting the proper optional coil is included in the section for Field Use.
Be sure to fill out and mail your warranty registration card to validate your warranty.
ASSEMBLY
Assembly of the PIranha is very simple, and requires no special tools. In fact, the only assembly necessary is to mount
the searchcoil to the end of the lower stem and connect the lower stem and the upper pole together.
1.
Take the lower stem (the one with the black isolator pole tip), and remove the screw and nut. Put two of the friction
washes into the recessed slots provided on the pole tip (where the screw fits through). Two sizes of friction washers are
supplied, one thick set and one thin set. Using the washers that fit best, insert the pole tip between the mounting ears of
the searchcoil and align the holes of the pole tip and washers with those of the mounting ears. The pole tip should fit
snugly.
2.
Insert the coil mounting screw through the ears of the searchcoil and pole tip, if the cable is in the way reverse the
direction of the screw and insert it from the other side.
3.
Install the thumb nut on the screw and tighten by hand.
4.
Depress the two buttons on the upper end of the lower stem, and slide it into the upper pole section. Push the lower
stem up so that the buttons click into the third set of holes from the end of the upper pole.
5.
Wrap the searchcoil cable around the pole making sure it is snug to the pole, leaving just enough slack near the
searchcoil to permit coil adjustment. Then connect the searchcoil connector into the matching connector found at the
back of the control box. Tighten it by hand.
Note:
Do not allow the cable to flop loosely over the searchcoil. The PIranha is sensitive enough to see the tiny wires in
the cable creating false signals caused by the moving wires.
CONVERSION
Obviously, converting the PIranha from pole mount to body/belt mount is simply a matter of removing the control box from
the upper pole and unwinding the cable. To remove the control box from the pole, depress the four spring buttons that hold the
mounting bracket and control box to the pole, and left. It is easiest to release one set of spring buttons at a time. Unwind the
searchcoil cable from the poles and fasten it to the lower stem with a velcro fastener, just above the black isolator tip, then
fasten the cable to the upper pole with the other velcro fastener, just below the foam hand grip.
Converting the PIranha back from body/belt mount to pole mount is simply a matter of reversing the above procedure.
ADJUSTMENT
The searchcoil angle and stem length should be adjusted so that the unit does not become uncomfortable or tiring to hold
after long periods of use. The detector should rest in your hand with arm relaxed allowing it to swing back and forth without
having to lift with the elbow or shoulder, while keeping the searchcoil as close as possible to the ground without touching. The
pole length is adjusted by depressing the spring buttons and extending or shortening the lower stem, till they click into the
holes that give you the most comfortable setting. The searchcoil should be about one inch above the ground while standing
erect. Adjust the angle of the searchcoil, so that the coil is parallel to the ground.
SPECIFICATIONS
TESORO Electronics, Inc., reserves the right to modify or improve the design without further notice.
CONTROLS
The PIranha has been specially automated so that only two controls are needed to make adjustments, one mounted on
the front panel of the detector and the other is mounted inside the control housing.
1.
ON/OFF BATTERY TEST THRESHOLD CONTROL.
This control is used to perform several functions: It turns the
instrument's power on and off. Turning the knob completely counterclockwise until it clicks disconnects the batteries from
the circuit, shutting the instrument off. When the knob is first turned on (clockwise), the detector will automatically test
its batteries, and give you a visible indication of their connection. Fresh batteries will cause a green LED to illuminate for
about 3 to 5 seconds. As the batteries age and become weaker, the illumination will be weaker and, and decay more
quickly. When the response is no glow from the LED it is time for new batteries. It is recommended to always use
alkaline batteries. The Threshold function of this control TUNES the detector to Threshold. This adjustment will be
explained further in the TUNING section of the manual.
2.
SIGNAL INDICATOR LIGHT.
A red light identified on the front control panel as "SIGNAL" will illuminate each time
the searchcoil is passed over a metallic object indicating the presence of a target. It is important to make sure you do not
have the Threshold set so sensitive that the detector responds to ground variations, hot rocks, other ground
mineralization, or electrical interferences as the SIGNAL light will illuminate even when the detector produces a false
signal caused by these.
3.
BATTERY TEST LAMP.
The PIranha features an automatic battery check that occurs each time the detector is
turned on. A fresh set of good batteries should illuminate the lamp for 3 to 5 seconds. As the batteries age the light will
become dimmer and its duration of illumination will shorten. If only a short, quick flash occurs or no light is present it is
time to replace the batteries. The PIranha requires 8 AA size alkaline batteries.
4.
VOLUME CONTROL.
The PIranha is equipped with a set of stereo piezo headphones that are hardwired to the
instrument for waterproof purposes. Because the instrument will be operated in different environments where the ambient
noise level varies, such as: near the crashing surf at ocean beaches, wearing head gear or listening over a regulator when
scuba diving, or detecting near a serene lake creates the need for a variable volume control. The volume control for the
headphones is found inside the control housing. To access this control simply unlatch the draw bolts holding the control
panel secure to the housing. Always make sure the control box is dry before opening. The volume control is found on the
left, the opposite side from the battery compartment. You will notice a small shaft used to adjust the volume level.
TUNING
Since the most troublesome adjustments of standard detectors have been automated in the PIranha, or are not
necessary with Pulse Induction, the tuning procedure for this detector is simply a matter of setting the desired Threshold tone
and headphone volume.
Pulse Induction does not require special adjustments in order to ignore the effects of wet salt or ground mineralization.
However, proper tuning is essential. To tune the PIranha, the Threshold control should be adjusted so that there is a barely
audible tone. If the tone is set too low or silent, some of the deeper or weaker targets may not be heard. If the tone is set too
loud, some deeper or weaker targets may not be heard due to audio masking. Setting the Threshold for silent operation will
cause some loss of depth, but may be necessary in extreme conditions in order to achieve smooth operation. A silent
Threshold may be necessary in some areas where gold nugget hunting in order to maintain a stable operation over hot rocks.
Since depth may be scarified, the PIranha should only be used as a nugget hunter when not other system is able to be
operated at the site.
You should not hear a change in the Threshold tone when lowering the searchcoil toward the ground. If a change occurs,
or you obtain an audio increase when lowering the searchcoil into saltwater, simply hold the coil still for a moment allowing
the auto tuning time to retune the instrument back to Threshold. Do not let the searchcoil raise at the end of your sweep as
this may cause some false signals. Always hold the coil parallel with the ground.
Pulse Induction will allow signal filtering once the desired signal is recovered from the pulse. However, for proper
operation, the pulse generator, searchcoil and input amplifier must be of very wide bandwidth. This makes the detector
susceptible to picking up any sources of electrical interference, such as 60 cycle power transmission noise. An absolutely
smooth Threshold may not be possible in my locations, and some rumble or motorboating may be present when the
Threshold is adjusted to the proper point. This is inherent in the design of a Pulse unit. Adjusting the Threshold either louder
or quieter is the only way to control this problem.
FIELD USE
The detector should be held in a position that is comfortable for you. Swing the detector from side to side in about a three
foot arc, overlapping succeeding strokes well. This motion is called a “sweep.” Go at a pace that is comfortable for you. In
fact, trying to hunt too fast in Discriminate may even cause a loss of depth in heavily mineralized locations.
It would be helpful to bury some coins and trash metal junk items in an area that you know is clear of other metal
objects, and then try the unit in its various modes. Check the area in All Metal Mode first to be sure its clear of trash then
bury the targets at least a foot apart, and from 2 to 6 inches deep to start. Make a map of the test bed to be sure you know
what each target is and how deep it is. Practice on these targets to familiarize yourself with your detector’s target response.
This will also help you learn the proper sweep rate to help insure against lost targets.
Try to keep your searchcoil height constant and close to the ground. Too often people tend to raise the coil at the end of
a sweep, much like a pendulum, especially if they are hurrying. Try to avoid this, as any increase in height will cause a
corresponding loss of depth. In areas with well kept lawns, the easiest way to maintain a constant searchcoil height is to
allow the coil to rest on the grass as you sweep from side to side. In rough and rocky areas it is best not to “scrub” the coil on
the ground, as the rocks will act like abrasives, and wear away the coil bottom (an optional coil scuff cover will protect against
this.) Sweep the coil as close to the ground as possible without touching. Avoid hitting the ground or rocks with the coil as
this may cause false signals that sound much like a desired target would. The higher you hold and sweep the coil above the
ground the less depth you'll be able to obtain.
If there is any doubt whether a target is good or not, DIG IT. If you don ’t dig any junk at all, you are surely passing up a
lot of good finds as well.
Once the detector has been tuned the auto tuning will maintain the Threshold at that level. Due to the auto tuning the
searchcoil must be moving while searching or pinpointing. If you stop the searchcoil over a metallic object or target the
detector will tune it out and return the instrument to the established Threshold. If you move the searchcoil slightly off the target
to one side, and hold it there momentarily, and then move it back over the target once again, the detector will automatically
retune to respond to the target.
SELECTING THE RIGHT SEARCHCOIL
Selecting the right searchcoil for the type of detecting you're doing will add greatly to your success. The PIranha come
with a standard 8" Printed Spiral coil which is a new and revolutionary design developed by Tesoro specifically for the PIranha.
This is an excellent overall coil since most people who operate PI instruments are usually searching large sandy beach areas
where targets are easy to dig and there is usually not an over abundance of trash. This coil will detect very tiny targets for its
size and provides excellent target separation while giving more ground coverage. However, it is not always the right coil for the
job. Therefore Tesoro has made it possible to interchange coils, and has developed a variety of its unique Printed Spiral
searchcoil in a selection of sizes.
In addition to the standard 8" open center searchcoil, two optional coil sizes are available for the PIranha. The 10 1/2"
open center coil is designed for areas where digging is easier, and where junk targets may not be too numerous. The 7 inch
coil will be particularly useful when searching for smaller targets, such as gold nuggets.
PINPOINTING
Move the coil slowly across the target from side to side and then from front to back at 90 degree angles. Raise the coil
slightly, slow the sweep speed, and shorten the sweep to narrow detection area enough that it's easy to tell where the coil
center is at the instant of the sound as you criss cross the target.
Another easy method is to sweep the coil from side to side across the target in very short sweeps, as you slowly move
forward and backward across the target, crisscrossing the target until you just barely get a response at one spot. Slow down
the sweep rate and shorten the sweeps until you just barely get a response at one spot. Again the target will be directly below
the coil center at the instant of response. Caution: this method will require some practice as well in order to get used to not
having your eyes follow the searchcoil. Typically it is easy to miss the spot by a fraction causing you to dig a large hole in
order to find the target is off to one side from where you started.
BATTERY REPLACEMENT
The PIranha is equipped with an automatic battery test circuit so that you can always be sure you are getting top
performance from it. The batteries should be checked after the detector has been on for about 10 minutes, and then
periodically as you are using it for long periods. To activate the batter test circuit, simply turn the detector off momentarily and
then back on. To test, follow the procedure described in the control section of this manual.
When testing the batteries, be
sure that the Mode Switch is in the Disc position, so that the All Metal threshold signal doesn't add to the battery
test signal.
The detector should beep loudly for about 4 or 5 seconds, with the sound slowly fading into silence, if the
batteries are fresh. As the batteries age, this sound less intense, and fades out quicker. When you just hear a brief buzz, or
not audio at all, replace the batteries.
To replace the batteries, pull the large knob on the battery door on the rear of the unit. The entire door will pop out.
Remove the batteries from the detector. Replace the new 9 volt batteries into the snaps, observing the polarity indicators.
Slide the batteries back into the detector, making sure that the battery clip lead is connected. Install the battery door flange
into the top of the cutout in the chassis, making sure that the plunger is still pulled out. Then push the plungers back in to
lock the door in place.
Should you desire to do so, rechargeable Nickel Cadmium batteries can be substituted for standard 9 volt cells. Individual
9 volt size cells are readily available at most electronic supply stores, as well as the chargers for them, and they can be
inserted into the standard holder used in your PIranha. The initial battery check reading will be slightly lower, but will not drop
as much with use, until the batteries are completely discharged.
DETECTOR PROTECTION CHECKLIST
Congratulations, you have just purchased a new metal detector, and we wish to thank you for choosing Tesoro.
So many people are disappointed when their new "state of the art" detector because less and less exciting to use, and
doesn't seem to go as deep anymore. There is something that you can do to keep your new detector working as good as
when it was new.
The most important thing is to simply to remember that your detector is an electronic instrument, and to treat it as such.
You wouldn't expect your TV set to operate properly if you stored it in the trunk of your car, would you?
We have generated the following list to help you take care of your detector and to help ensure that you do not void its
warranty. If you will follow its guidelines, you will find your detector will not let you down.
l
Operate your detector exactly as recommended in this instruction manual.
l
Do not attempt to modify or repair the detector's electronics; caution: opening of control housing may void your
warranty.
l
Cable is hard wired into search coil, do not attempt removal of the spring retainer on the search coil housing.
l
Use only highquality carbonzinc, alkaline, or nicad batteries. Never substitute a different voltage. Brand should not
be mixed. Do not attempt to modify the power supply system.
l
Never spray lubricants such as WD40 or any type of cleaners, sealants or other chemical preparation on or into the
detector.
l
Avoid banging the searchcoil against rocks or foundation walls.
l
Remove and clean out scuff covers periodically to avoid build up of mineralized dirt particles which will affect
performance.
l
After each use, clean the detector with a soft cloth to remove dust, moisture, and other contaminants.
l
Do not transport or store your detector in the trunk of your car.
l
If your detector has a protective spring at the coil cable connector, be sure that the spring does not work its way
inside the plug, causing a short. (On Tesoro detectors, the spring should extend approximately 5/8th from the base of the
connector.)
l
Keep cables properly wound around the pole stems and protect them during use. Floppy, pinched, or cables that
become snagged during use may short, causing erratic noises or unnecessary replacement of the searchcoil.
l
Protect your detector from dust, moisture, and extreme temperatures during storage. Avoid storing it in places such
as attics, basements, or garages. When shipping, use the original factory carton or similar heavyduty container; a one
inch minimum clearance of padding around the detector must be provided when shipping.
l
Treat your detector as you would any sensitive electronic instrument. Though ruggedly constructed and designed to
withstand the demands of normal treasure hunting applications, it is not intended to be improperly operated or abused.
Under the copyright laws this documentation may not be copied, photocopied, reproduced, translated or reduced to any electronic or
machine readable form, in whole or in part, without the prior written consent of Tesoro Electronics Incorporated, except for the private
use of a PIranha owner or operator, or in a manner otherwise described in this documentation.
© 19951996 Tesoro Electronics Incorporated. All rights reserved. Printed in the United States.
WARRANTY SERVICE
Your Tesoro metal detector is covered by a
Limited Lifetime Warranty
, the
terms of which are listed below. If your metal detector should require service, you
may return it to the Tesoro factory, or tone of the factory authorized service
centers. Contact the factory for the name and address of the nearest service
center.
If you have any questions, don't hesitate to contact the factory.
WATAERPROOF METAL DETECTOR WARRANTY
This warranty gives you specific legal rights, and you may have other rights
which vary from state to state.
This instrument is warranted to be free of defects in material and workmanship
as long as it is owned by the original consumer purchaser. This warranty is not
transferable, and is valid only if the warranty registration card has been completed
and mailed within 10 days of purchase.
During the first two years, TESORO will, at its option, repair or replace any
instrument covered by this warranty, without charge, except for transportation
charges, at its factory in Prescott, Arizona, or at one of its authorized repair
centers. After two years from date of purchase, TESORO will replace defective
parts at no charge except a nominal labor change and transportation charges.
This warranty excludes batteries, damage caused by leaky batteries, cable
breakage due to flexing on body mount units, and wear of the searchcoil housing.
Also excluded are instruments which have been abused, altered, or repaired by an
unauthorized party.
If warrant service should be necessary, contact the factory for nearest repair
center.
Tesoro Electronics, Inc. 715 White Spar Road Prescott, AZ, USA 86303 1928 771 2646
Operating Frequency
900 kHz
Searchcoil Type
Printed Spiral
Searchcoil Size
8" Diameter
Cable Length
Approx. 3’
Audio Frequency
Approx. 900 Hz
Audio Output
Stereo Piezo Headphones
Weight (may vary slightly)
less than 4.5 lbs
Battery Requirement
(8) AA DC (alkaline)
Battery Life (typical)
10 to 20 hours
Optimum Temperature Range 30° to 100° F
Operating Modes
Motion (auto tune)
All Metal
Maximum Depth Rating
200 ft.
Home
