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Page 36
12.8 Determining if an instrument or pH electrode is faulty
The following test can be performed to help determine if the
MC-81
or the pH
electrode is faulty.
1.
Initialise the
MC-81
(see section 9).
2.
Disconnect the pH electrode.
3.
Connect the centre pin of the
pH
connector with the outside frame of the
connector, using a short piece of wire or a paper clip etc.
4.
The meter should read approximately 7.00. If you press the
key, the
MC-81
will calibrate to around 6.88 pH, depending upon the temperature
readout.
5.
If the
MC-81
is operating correctly, the reading should be totally stable with
the wire firmly in place. If not, the meter requires servicing.
6.
Now carefully disconnect the wire from the centre pin only (make sure the
other end of the wire remains connected to the outside frame of the
connector).
7.
After and initial small jump, the reading should steadily drift away from 7.00
(either up or down) at a rate of approximately 1 pH or less every 3 seconds. If
the drift rate is faster than this, then input circuitry of the
MC-81
is faulty and
requires servicing.
12.9 Instrument software version number.
If you need to phone or fax TPS for any further technical assistance, the version
number of your
MC-81
firmware may of benefit to us. Please obtain the version
number as follows, before phoning or faxing:
1.
Switch the
MC-81
on by pressing the
key.
2.
While the model is being displayed, press the
key.
3.
The unit will now display the model and version number,
eg:
TPS MC81
Ver 1.1