YSI Professional Plus - Manual (Page 35)

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GENERAL MAINtENANCE - SENSoR PoRtS
It is important that the entire sensor connector end be dry when installing,
removing or replacing. this will prevent water from entering the port. once
a sensor is removed, examine the connector inside the port. If any moisture is
present, use compressed air to completely dry the connector or place directly in
front of a steady flow of fresh air. If the connector is corroded, return the cable
to your dealer or directly to an YSI Repair Center.
Remove sensors upside down (facing the ground) to help
prevent water from entering the port upon removal.
sensor MaIntenance
SENSoR MAINtENANCE - DISSoLVED oXYGEN
Membrane Cap Installation
the Do sensor (Polarographic and Galvanic) is shipped with a dry, protective
red cap that will need to be removed before using. Remove the protective cap
or used membrane cap and replace it with a new membrane cap following these
instructions:
Remove the sensor guard to access the sensor tip.
Unscrew and remove any old membrane cap by holding the
sensor when unscrewing the membrane cap and discard.
thoroughly rinse the sensor tip with distilled or DI water.
Fill a new membrane cap with o2 sensor electrolyte
solution that has been prepared according to the
directions on the bottle. Be very careful not to
touch the membrane surface. Lightly tap the side
of the membrane cap to release bubbles that may
be trapped.
thread the membrane cap onto the sensor. It is normal for
a small amount of electrolyte to overflow.
Polarographic Sensors - Model # 605203
the KCl (potassium chloride) solution and the membrane cap should be changed
at least once every 30 days during regular use. In addition, the KCl solution and
membrane should be changed if (a) bubbles are visible under the membrane; (b)
significant deposits of dried electrolyte are visible on the membrane; and (c) if
the sensor shows unstable readings or other sensor-related symptoms.
During membrane changes, examine the gold cathode at the tip of the sensor
and the silver anode along the shaft of the sensor. If either the silver anode is
black in color or the gold cathode is dull, the sensor may need resurfaced using
the fine sanding disks included in the membrane kit. Do not sand the electrode
every membrane change as this is not routine maintenance. In fact, visually,
the anode may appear tarnished and operate just fine. YSI recommends using
the 400 grit wet/dry sanding disks to resurface the electrodes if the sensor has
difficulty stabilizing or calibrating after a membrane change.
to resurface the sensor using the fine sanding disk, follow the instructions
below.
Gold Cathode:
For correct sensor operation, the gold cathode must be textured properly. It can
become tarnished or plated with silver after extended use. Never use chemicals
or abrasives not recommended or supplied by YSI.
First dry the sensor tip completely with lens cleaning tissue. Wet a sanding disk
with a small amount of clean water and place it face up in the palm of your hand.
Next, with your free hand, hold the sensor in a vertical position, tip down. Place
the sensor tip directly down on the sanding disk and twist it in a circular motion
to sand the gold cathode. the goal is to sand off any build-up and to lightly
scratch the cathode to provide a larger surface area for the o2 solution under
the membrane. Usually, 3 to 4 twists of the sanding disk are sufficient to remove
deposits and for the gold to appear to have a matte finish. Rinse thoroughly and
wipe the gold cathode with a wet paper towel before putting on a new membrane
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