The GXL-24 Pro Electronic Gold Tester
Efficient, non-destructive determination
of gold karat values from a to 24 karats
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INTRODUCTION
The GXL-24PRO GOLD TESTER™ is a high technology professional
digital instrument, developed for efficient, non-destructive determination of
gold karat values from 6 to 24 karats. The principle of the GXL-24PRO Gold
Tester is based on an electrochemical process which measures the decay of
electrical energy between the sample under test and the cathode in the sensor.
The result is processed in karat and European Standard unit value. The
GXL-24PRO Gold Tester™ determines platinum and the gold karatage in the 6-24
karat range in alloys commonly used in the jewelry industry. The base metals are
found in these alloys are: copper, silver, zinc and nickel. There are other
types of gold (yellow, white and red/pink) that use these metals in different
proportions. The most commonly used gold on the market is yellow, which
utilizes as base metals, silver and copper in a silver to copper ratio of 2:1 up
to 1:2. The Gold Tester will only give accurate results in commonly alloyed gold
compositions. White gold's base metals consist of a small amount of copper, over
18% nickel, less than 5% of silver, and the rest is made up of zinc. We recently
noted that some low karatage (below 18k) has high copper content. If you obtain
low readings on what appears to be 14k marked yellow gold, the alloy may have
higher than normal copper content. Use the "R" button to obtain a correct
reading. Red/pink gold's base metals are made up mostly of copper, less
than 5% silver and a small amount of zinc. The GXL-24PRO is not
recommended for dental gold alloys. The mixture of palladium that exists in
dental gold alters karat determination and may give a higher karat determination
than actually exists. Besides determining the karatage of gold, the Gold
Tester is also able to distinguish gold plated and gold filled items. In cases
when it is unknown whether an object is solid gold or gold plated, the
manufacturer recommends that a small test point on the object be filled or
penetrated with a needle to assure electrolyte penetration to the base material.
IMPORTANT RECOMMENDATIONS
The precious alloys with gold amounts from 6
(250) to 24K (999.0) require the user to observe the following specific test
conditions:1. The object's test point must be cleaned thoroughly and vigorously
with an eraser before each test. (Note: The eraser tip must be clean before use
and free of residual from prior cleanings.) Herringbone and rope chains are
composed of a lot of solder. Low karat readings may be due to the testing of
lower karat solder. Do not test the shank of a ring due to the fact that this
area may have been soldered. Do not test or rely solely on the testing of
clasps. Although the clasp may be in the correct karatage, the rest of the chain
may be under
-karated
Important:
VIGOROUS, THOROUGH CLEANING IS ESSENTIAL FOR ACCURATE RESULTS ON HIGH KARATAGE
(OVER 18K) GOLD.
2. The platinum contact inside the
sensor's cone must be cleaned with a cotton swab moistened with cleaner and
dried before use and after 6-8 continuous tests.
3. The nozzle slots must be cleaned from
dried or used gel and a drop of gel should be dispensed and disposed before each
test.
| 4. Use a minimum amount of gel for
testing, especially for high karatage gold tests (above 18k). After
dispensing a small dome of gel on the sensor tip wipe the tip on a piece of
tissue paper by touching the tip to the tissue while holding the sensor in a
vertical position to the paper. Do NOT use a dome of gel or an amount of gel
that causes excess gel to appear along the edge of the sensor tip while
testing. If there is not a sufficient gel to test the instrument will read
"TRY AGAIN", but will not give an erroneous reading. |
 |
5. The machine is not infallible and from time
to time, for a variety of reasons, you may get a reading, high or low, which is
inconsistent with your understanding of the expected karatage. ALWAYS make
additional readings in other locations on the jewelry with special attention to
cleaning, to verify unusual readings
6. Very fine (thin) chains are very
susceptible to crushing if the dispenser is pressed too hard on them.. always
avoid pressing the dispenser against these thin chains while assuring gel
contact. Two or three tests are recommended.
7. Solder joints and certain spots on
heavy castings may give erroneous readings due to the solder composition or
non-homogeneous gold. Re-test new area if result is suspected.
8. Many Italian gold chains and necklaces are coated with a
wax-like material. If the readings are suspected, clean area to be tested by
heavy erasing, or a drop of nitric acid. If the karat value increases with heavy
erasure, you may be assured the gold is coated. In all cases, nitric acid has
removed the coating.
9. In heavily worn/used pieces, clean thoroughly with an
eraser or non-acetone nail polish remover to remove dirt and skin oils.
10. A pin prick or scratch on suspected plated pieces is
often required to allow gel penetration to the base material to obtain an
accurate result.
SPECIFICATIONS
The GXL-24PRO Digital Unit Dimensions:
| Length |
Width |
Depth |
Weight |
Power |
| 7 1/4" (18.4 cm.) |
3 3/3" (8.57 cm.) |
9" to 1.1" (2.28 cm. to 2.79 cm.) |
1/3 lb. (165 grams) |
Two 9 volt alkaline batteries |
Optional: DC converter from 120 V, 60 Hz AC, or from 220 V,
50 Hz AC, specifically designed for the GXL-24PRO
WARNING: DO NOT USE ANY OTHER CONVERTERS OTHERWISE THE UNIT WILL BE DAMAGED.
Gold Tester Testing Range: From 6 (250) to 24k
(999.0) of gold value.
THE GXL-24PRO DISPLAY UNIT The
GXL-24PRO Display Unit is a computerized controller which analyzes a signal from
the electrochemical process and converts it to karat and European Standard value
in an alpha-numeric display. (See Diagram).
GOLD VALUE
DATA
The GXL-24PRO Display Reading Display Unit
 |
- 1. GXL-24PRO Display Unit
- 2. Alpha-numeric Display Window
- 3. Selection Buttons
- 4. Sensor Outlet
- 5. Converter AC/DC Outlet
- 6. ON/OFF Power Switch
|
The unit will display one of the following values in the LC Display depending
on the alloy under test:
Start - Buttons / Gold Color
Indications
|
Y-YELLOW |
W-WHITE |
R-RED (pink) |
G-GREEN |
|
not gold |
not gold |
not gold |
not gold |
| 6-7KY |
250-291 |
6-7KW |
250-291 |
6-7KR |
250-291 |
6-7KG |
250-291 |
| 8KY |
333 |
8KW |
333 |
8KR |
333 |
8KG |
333 |
| 9KY |
375 |
9KW |
375 |
9KR |
375 |
9KG |
375 |
| 10KY |
416 |
10KW |
416 |
10KR |
416 |
10KG |
416 |
| 11KY |
458 |
11KW |
458 |
11KR |
458 |
11KG |
458 |
| 12KY |
500 |
12KW |
500 |
12KR |
500 |
12KG |
500 |
| 13KY |
541 |
13KW |
541 |
13KR |
541 |
13KG |
541 |
| 14KY |
583 |
14KW |
583 |
14KR |
583 |
14KG |
583 |
| 15-16KY |
625-667 |
15-16KW |
625-667 |
15-16KR |
625-667 |
15-16KG |
625-667 |
| 17KY |
708 |
17KW |
708 |
17KR |
708 |
17KG |
708 |
| 18KY |
750 |
18KW |
750 or more |
18KR |
750 |
18KG |
750 |
| 19KY |
792 |
|
|
19KR |
792 |
19KG |
792 |
| 20KY |
833 |
|
|
20KR |
833 |
20KG |
833 |
| 21KY |
875 |
|
|
21KR |
875 |
21KG |
875 |
| 22KY |
917 |
|
|
22KR |
917 |
22KG |
917 |
| 23KY |
958 |
|
|
23KR |
958 |
23KR |
958 |
| 24KY |
999 |
Platinum |
|
|
|
|
|
NOTES: The color of the gold
depends on the base metal(s) used. The second number on the LCD Display
(250-999) indicates European standard of gold value
The Mechanical Sensor
The Mechanical Sensor for the GXL-24PRO
Gold Tester consists of two parts: (1) the sensor body; (2) a polyethylene tube
with gel. The polyethylene tube must be placed inside of the sensor's body
before beginning a test.
When using the Sensor, be sure that:
The sensor nozzle platinum contact and slots are clean.
Use a cotton swab moistened with cleaner to clean the platinum contact and dry
it before commencing tests and after every 6-8 repetitive tests.
Dispense a drop of gel before the start of each test.
It is recommended that the sensor be thoroughly cleaned
with Tri SC-10 sensor cleaner when the gel tube is changed or if gel is
backing up around the plunger.
LOADING / CHANGING THE
POLYETHYLENE GEL TUBE
 |
1. Take off the nose cone cap (See Diagram).
2. Remove the Stationary Cap by turning the
Stationary Cap (light colored barrel) counter-clockwise. Please remember
that the Stationary Cap and the Rotary Cap are undetachable.
3. Insert the Feed Screw Engagement into the
appropriate slot of the Rotary Cap. Be sure that the Feed Screw is fully
engaged.
4. Take off Tube Cap. |
5. Insert the polyethylene gel tube, until it is fully
lodged in the sensor and turn the light colored barrel clockwise until fully
fastened. Do not turn the dark colored top barrel clockwise or it will damage
the mechanism.
6. Turn the dark colored top barrel counter clockwise
until the first drop of gel appears at the sensor nozzle (about 1020 times to
fill the cone). The Mechanical sensor of the GXL.24PR0 Gold Tester
consists of two pans: (I) the sensor body: (2) a polyethylene tube with gel. The
polyethylene tube must be placed inside Of the sensor's body before beginning a
test.
OPERATION PROCEDURE
 |
1. Load the polyethylene gel tube into the sensor (see
procedure on Page 11 or this instruction manual). 2. Connect the long
black wire to the sensor's plug outlet, the short black wire connector to
the display unit, and the red wire to the testing plate as shown in Diagram.
3. Turn the unit "ON." The unit should display "Clean sensor tip". |
4. Before the start of testing, use the sensor nozzle cleaner
or any small sharp instrument to remove dried or used gel from the dispenser
opening and slots and clean the sensor tip thoroughly with a cotton swab wetted
with alcohol, then dry the tip thoroughly.
5. Prepare the item for testing by thoroughly vigorously
cleaning a spot on the jewelry with the eraser provided. When testing the 1
8-24K (750-999) gold, be sure that the eraser tip does not have a black deposit.
Clean the eraser on a paper. Also clean the area on the item to be clipped and
place cleaned item in clip.
6. The testing point on the object should be close to, BUT NOT
TOUCHING, the alligator clip. Be sure this point is far enough away from clip so
that gel does not touch the alligator clip as this will cause the clip to
corrode and give erroneous results.
7. Place a tissue, paper towel or rag under the tip of the
sensor and, holding the sensor on the vertical position with the nozzle down,
twist the Rotary Cap counter clockwise, a click at a time, until a drop of gel
appears on the tip. Wipe this first drop of gel on the towel and turn (usually
one or two clicks) until a fresh drop appears. Use a minimum amount of gel for
testing, especially for high karatage gold tests (above 18k). After dispensing a
small dome of gel on the sensor tip wipe the tip on a piece of tissue paper by
touching the tip to the tissue while holding the sensor in a vertical position
to the paper. Do NOT use a dome of gel or an amount of gel that causes excess
gel to appear along the edge of the sensor tip while testing. If there is not a
sufficient gel to test the instrument will read "TRY AGAIN", but will not give
an erroneous reading. Do not let gel or sensor nozzle touch the alligator clip!
8. Press one of the following buttons: Y-Yellow, W-White,
it-Red (Pink), G-Green, depending on the color of the gold.
9. Maintain the sensor tip flat against the sample
(perpendicular to sample) and hold firmly in the same position approximately
five (5) seconds while the instrument displays the gold value in karat and
European standard. IMPORTANT: After initially turning the unit "ON",
perform a pre-test on the item. Immediately after the PRETEST, retest the gold
item to determine the karat value of the item. On retest, dry and re-clean the
test point on the item, dispense and dispose one drop of gel (do not re-clean
the sensor tip). Dispense a second drop and retest. This pre-test procedure is
essential to neutralize any residual electrical charge remaining in the sensor
tip after storage.
10. After every 6-8 continuous tests, clean the platinum
contact of the sensor with cleaner and dry the contact. NOTE: On high
karatage gold (greater than 17 karat, 708), the first test may result in a lower
karatage reading due to the residual charge. It is always preferable to take at
least two or three readings on high karatage gold. Repeatable readings on high
karatage samples will assure the user of maximum accuracy.
IMPORTANT: ALWAYS AVOID ANY RESIDUE AND MOISTURE ON THE
PLATINUM CONTACT BEFORE TESTING. DO NOT REPEAT A TEST ON THE SAME POINT WITHOUT
ERASER CLEANING.
TESTING OBJECTS LARGER THAN THE
ALLIGATOR CLIP
 |
When testing objects larger than the alligator clip, unhook the red wire
from the testing plate and proceed with the test as per instructions but
this time touch the tip of the red wire to object. |
TESTING GOLD CHAINS THE SURFACE
OF WHICH IS COVERED IN AN ORGANIC MATERIAL
Some gold chains are covered by organic materials in order to add luster to
the surface. These materials can alter the results of a gold test. In order to
avoid this problem, an inch or two of the chain should be thoroughly cleaned
with an eraser. The alligator clip and the sensor should be placed upon the
chain well inside the cleaned and stretched area. As a result, there is an
electrical contact between the alligator clip and the testing point. A
suggestion on how to "RUB OFF" the organic substance in some Italian triple and
quadruple herringbone chains is to use a small amount of non-acetone nail polish
remover if the organic substance coating is thin, or to put a small drop of
nitric acid in the test spot just enough to burn off the organic material. Wipe
the test spot before touching the same with the sensor. Please note
that 20K (833) - 24K (999.0) chain links are soldered with gold-solders which
have a karatage lower than the chain link. If a test point is on solder,
the instrument may show a lower karat value. Special caution is advised
with rope or diamond cut chains. Two or more tests are recommended on different
links to obtain accurate results. Good contact between the sensor and the test
point is essential for accurate results.
CARE AND MAINTENANCE OF THE
GXL-24PRO GOLD TESTER
1. Before the start of testing, use the sensor nozzle cleaner
or any sharp instrument to remove dried or used gel from the dispenser opening
slots, and clean the sensor tip thoroughly with a cotton swab wetted with
cleaner; then dry the tip thoroughly.
2. After each 6-8 consecutive tests, clean the platinum
contact inside the sensor's cone with a cotton swab moistened with cleaner, and
dry the contact. IMPORTANT: ALWAYS AVOID ANY RESIDUE AND MOISTURE ON THE
PLATINUM CONTACT BEFORE TESTING.
3. Always replace the sensor's nozzle cap when sensor is not
in use to prevent gel from drying up and clogging the opening.
4. After removing the gel tube from the sensor, wash the
sensor with distilled water immediately, to prevent the drying of gel inside the
sensor. It is recommended that the sensor be thoroughly cleaned with Tri SC-10
sensor cleaner when the gel tube is changed or if gel is backing up around the
plunger.
5. Dispose of a drop of gel before each test.
6. Never remove the tri cable from the sensor's outlet by
pulling wire. Pull the cable by the plug only. 7. The gels
have a shelf life dependent on temperature. The gels should be stored at a
temperature of 80�F (26.6 �C) or less. For longevity, it is
recommended that the gels be stored in a refrigerator when not in use. DO NOT
FREEZE! The shelf life has been exceeded if the gels turn liquid. When stored
below 80�F (26.6 �C), the gels will not liquefy in less than six months and
can be expected to last in excess of one year. As long as the solution is in a
gel state, it will provide accurate readings.
8. Be sure to use TB-24 Pink color gel with the GXL24PRO Gold
Tester.
Trouble Shooting
PROBLEMS |
SOLUTIONS |
| Brown spot on test surface |
Thoroughly rub the spot with an eraser. |
| On gold item display unit reads "TRY AGAIN" continuously |
Check the wire contacts and connections or change wire set. |
| Turning sensor's rotary cap becomes difficult to turn or is
tight; or a changed/reduced karat value appears in display |
Gel tube is almost empty or empty. Put in new gel tube. |
| Inaccurate or different readings |
Thoroughly clean sensor's contact, slots, and testing item.
Keep gel away from alligator clip |
| Gel does not come out |
Clean sensor nozzle and slots with a cotton swab wetted with
alcohol, and dry the tip |
NOTE: Always try to select a testing point close to the alligator clip
but make sure that the gel does not touch the alligator clip to prevent
corrosion. Do not repeat a test on the same point without eraser cleaning.
It is important to remember that a gold filled object's reading will be reduced
after each additional eraser cleaning on the same spot. A solid gold object will
not have reduction in its karat reading even with continuous erasing. In case
the user doubts that the object is solid. gold, it is recommended that the user
make a tiny hole with a needle at the test point before a test. The
GXL-24PRO Gold Tester must be used in accordance with these instructions, to
obtain full satisfaction with the device.
IMPORTANT DO NOT TRY TO OPEN OR DISASSEMBLE THE DISPLAY UNIT. The parts
and connections inside are very delicate integrated circuits. Any attempt to
disassemble may disturb these circuits resulting in unsatisfactory reading or
over all performance of the GXL-24PRO Gold Tester. The warranty will not apply
to any units where an attempt to disassemble is established.