Thermo Fisher Scientific CyberScan DO 300 - Manual (Page 42)

Instruction Manual DO 300
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9.3 Membrane/O-ring Replacement (Optional Procedure)
It is recommended only experienced service personnel can perform this procedure.
This procedure is OPTIONAL, and should only be performed if you have new membrane and
O-ring. You are also required to have a membrane installation tool. These items are available
as optional accessories in the Accessories section.
1. Pull off the probe guard. See figure on right.
2. Unscrew the membrane cap from the probe.
3. Hold the probe under hot running water and brush
away the white oxide on the cylindrical anode with a
stiff plastic brush – do not use metal cleaning
material.
4. If the cathode has any deposits, remove them with a
light scouring powder. Do not polish the cathode.
5. Using the installation tool, unscrew and remove the
membrane lock from the membrane cap. See Figure
36.
6. Remove the membrane and O-ring. Discard both.
7. Rinse the membrane cap and membrane lock in tap
water.
8. Install a new O-ring inside the membrane cap.
9. Install a new membrane. Make sure the membrane
covers the O-ring all around its circumference. See
Figure 37.
NOTE: Membrane replacements available from Oakton
Instruments only.
Figure 35: Positioning of O-ring
& membrane