CORNING 440 pH Meter - Problem Solving; Meter Test and Reset

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109118-1 Rev. A, 10/96
3.3 Maintenance (cont)
3.3.2 Electrode Maintenance (cont)
Oil contamination - Carefully clean the tip of the
electrode using a cotton swab soaked with alcohol or
acetone. The tip of Glass body electrodes can be put
directly into organic cleaners but do not put plastic or
epoxy body electrodes into organic solvents. Rinse the
electrode and soak in pH 7.0 buffer until stable.
All others - Soak tip of the electrode in 0.1 M
Hydrochloric acid for one hour. Rinse the electrode and
soak in pH 7.0 buffer until stable.
3.4 Problem Solving
Most problems are caused by electrode faults rather than by the
Model 440 but power fluctuations can corrupt calibration values
being held in the meter memory.
3.4.1 Meter Test and Reset
To assure that the meter memory and calibration points have not
been corrupted by power fluctuations, perform the Meter Test
and Reset as follows:
1. Disconnect the power plug from the back of the meter.
2. Press and hold and reconnect the power plug. The
display first shows the test sequence, with all segments
showing, then displays an 01.
3. Release Press and the display shows 02.
Press the displays shows 03.
Press , , , and
in turn and check that the display reads 04, 05, 06, 07, 08.
3
read
read
mode
<
<
buffer
auto
read
on/off
cal