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CHECKING THE INTEGRITY OF A GAMRY CELL CABLE:
Of all the components of a Gamry system, the Cell Cable is the one that is
constantly being flexed and exposed to corrosive environments. This test
may take a couple of minutes, but if it identifies a problem, it will be
time well-spent. If the Cell Cable is determined to be faulty, this
can prevent a Potentiostat from a needless trip to Gamry for repair. This
presents the rare opportunity to save both time and money...especially for
our international users.
We urge you to consider purchasing a spare Cell Cable. If you only
have one Cell Cable, expect it to fail sooner or later. Having an
inexpensive replacement will avoid any downtime.
SYMPTOMS OF SUSPECT LEADS:
There are other reasons that you may see these specific symptoms, but here
is what you will encounter if the cell cable is damaged:
1. During the Calibration routine, your Potentiostat passes the early
internal adjustment tests, but fails the later "Applied Pstat" or "Applied
Gstat" tests. This could be a general cell cable problem. Make sure
the cell cable is firmly connected to the Potentiostat and the leads are
correctly attached to the appropriate version of the Universal Dummy Cell.
2. The Working Sense (blue) and Reference (white) leads are the two inputs
to the Potentiostat's electrometer. The electrometer is the
potential-measurement device. If the measurement of Potential (Vm) drifts
from the value you requested, the problem may lie with one of these two
leads. In particular, if the voltage measurement gets to +/-11 Volts,
there is a good chance one of these leads is damaged. Intentional
resistors are installed in both of these leads. Both the Working Sense and
Reference leads should measure ~ 260 Ohms.
3. The Working (green) lead is the electrode that measures the current in
the cell. You can suspect this lead is damaged, if your system always
measures 0 Amps of current. Measuring 0 Amps doesn't stress the
Potentiostat, so you will not see any overloaded data. All displayed
points will be blue. The Working Electrode lead should measure 0 Ohms.
4. The Counter (red) lead is the output of the Control Amplifier. The
Control Amplifier is the device that delivers the necessary current to
control the cell. If there is a break in the Counter Electrode lead, the
Control Amplifier will not be able to control the cell. Your data will be
displayed in the Framework with red markers and be accompanied by a "CA
OVLD" message. The Counter Electrode Lead should measure 0 Ohms.
5. Also, the Counter Sense and Ground leads should measure 0 Ohms.
Of course, if you have multiple Cell Cables (for a MultEchem or
Multiplexer), substituting a known good Cell Cable is the quickest test.
The following are tests for a broken lead, the more common occurrence.
To test for a lead inadvertently shorted to its neighbor, you can test
resistance between each pin surrounding the correct pin and the correct
cell lead. Each surrounding pin should measure infinite resistance.
You will need a digital multimeter capable of measuring resistance (any
electronics shop should certainly have one).
The pin number is printed on the black section inside the connector beside
the base of the pin. You may need to angle it or use a flashlight to see
it.
DIAGNOSTIC CHECK OF A GAMRY SERIES G/PCI4/ PC4/ECM8 CELL CABLE:
Note the Working Sense and Reference leads should measure ~260 Ohms.
The Working and Counter leads should measure 0 Ohms.
1. Disconnect the Cell Cable from the back of the PCI4 Potentiostat.
2. Set the Multimeter to read Resistance in Ohms.
3. Connect one terminal of the Multimeter to the Working Sense (blue)
lead....Connect the other end to Pin # 1. You should measure ~260 Ohms.
4. Connect one terminal of the Multimeter to the Reference (white)
lead....Connect the other end to Pin # 6. You should measure ~260 Ohms.
5. Connect one terminal of the Multimeter to the Working (green)
lead....Connect the other end to Pin # 3. You should measure 0 Ohms.
6. Connect one terminal of the Multimeter to the Counter (red)
lead....Connect the other end to Pin # 9. You should measure 0 Ohms.
A broken cell cable is indicated by a very high (infinite) resistance.
This indicates that the cell cable is damaged and needs to be replaced. We
do not repair cell cables.
There is a complete description in Table D-1 on Page 6-11 of the manual
http://www.gamry.com/Support/Manuals/V5/PCI4.pdf, which coordinates the
Pin/Lead combinations.
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Continue on to step 5 only if you measure very high or infinite
resistance in the preceding steps.
5. Using a Philips head screwdriver, locate and remove the two screws
located on the hood of the D-connector that plugs into the front-panel
of the Reference 3000 Potentiostat. This will give access to the fuses.
The fuses are very small (2.5 x 6 mm).
6. Connect your Multimeter terminals to each side of one fuse to test
the Resistance. Functioning fuses will measure 0 Ohms. Remove any
faulty fuses by using a pair of tweezers, and replace them with spares
that were shipped with your Reference 3000 cables.
7. Reassemble the D-connector and repeat steps 3 and 4 to verify proper
continuity throughout the Counter/Working cable.
The indication of a broken Counter/Working cable is that either the
Working or Counter leads will measure a very high (infinite) resistance
after the fuses have been checked. This indicates that the cable is
damaged and needs to be replaced. We do not repair cell cables.
Note the Working
Sense, Counter Sense, and Reference leads should measure ~260 Ohms.
Verifying the Sense
Cable:
1. Disconnect the Sense cable from the front of the Reference 3000
Potentiostat.
2. Connect one terminal of the Multimeter to the Working Sense (blue)
lead…Connect the other terminal to Pin # 8. You should measure ~260
Ohms.
3. Connect one terminal of the Multimeter to the Counter Sense (orange)
lead…Connect the other terminal to Pin # 11. You should measure ~260
Ohms.
4. Connect one terminal of the Multimeter to the Reference (white)
lead…Connect the other terminal to Pin # 13. You should measure ~260
Ohms.
The indication of a broken Sense cable is that any of these three tests
will measure a very high (infinite) resistance. This indicates that the
cell cable is damaged and needs to be replaced. We do not repair cell
cables.
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