Maintenance & Troubleshooting; The Readout Module; Sensors; Troubleshooting Guide - Martek MARK 22 Operation Manual

6 - MAINTENANCE & TROUBLESHOOTING
6.0 T R
HE EADOUT
The Mark 22 monitor is housed in an ex-
truded aluminum case coated and painted
to withstand exposure in a marine environ-
ment. However, the Mark 22 is not water-
proof. Care should be taken to avoid mois-
ture settling on the front panel. If water ex-
posure is a problem, a large plastic zip-lock
bag can be used to protect the Mark 22 from
exposure.
While the Mark 22 is portable, it should
be treated like a quality laboratory instru-
ment. Excessive banging or dropping of the
monitor should be avoided.
The lamp used in the Mark 22 display has
a rated life-span of over 7,500 hours. The
lamp should be used sparingly when sur-
rounding light is poor.
are available from Martek Instruments.
6.1 S
ENSORS
The temperature sensor requires no main-
tenance.
The Martek Conductivity Reference Cell
should be kept dry when not in use. After
each use and before the sensor is stored, iso-
propyl alcohol should be flushed through the
sensor to remove any dirt or salt build-up.
If possible, use pressurized air to remove any
remaining moisture.
The pH sensor should be kept in its soaker
bottle or cap at all times when not in use.
Potassium chloride (KCl) or a pH buffer so-
lution should be used in the soaker bottle or
cap. Do not use distilled water.
The connectors should be kept free of dirt
and the cables carefully coiled when not in
use.
34
M
ODULE
Replacement lamps
6.2 T
ROUBLESHOOTING
There may be instances where the Mark
22 does not respond in the manner desired.
This section deals with the errors most com-
monly encountered and offers suggestions to
overcome potential problems.
1. The Mark 22 display indicates "No pH
or Conductivity Sensor connected" even
though sensors are hooked up to the
monitor.
ANSWER: Check to see that the sensors
are hooked up to the correct connectors
on the monitor. If so, turn the Mark 22
off and then back on again to recycle the
p r o g r a m .
2. The Mark 22 fails to respond to any key
commands.
ANSWER: Make sure that the Mark 22
is not in the LOGGING mode. This is in-
dicated by a black box or the letter "p" in
the upper right hand corner of the dis-
play. If so, press the LOG key to disable
the logging function.
3. The Mark 22 displays "MEM ERROR
REDO CALIBRATION" after power is
turned on.
ANSWER: The Nicad batteries used for
internal memory power in the Mark 22
may not be charged. Charge the Mark 22
for at least 24 hours to allow the batteries
to charge up.
4. Conductivity readings are not close to
the suspected value of the sample be-
ing measured.
ANSWER: Check to see that the correct
"K" factor, range, and temperature com-
pensation formula have been inputted
Martek Instruments, Inc.