Teledyne MD300 - Oxygen analyzer and monitor (Diving) - Manual (Page 33)

Portable Oxygen Monitor Service Manual
Teledyne Analytical Instruments 33
Symptom Why What To Do
The unit has stopped
working and the LCD is
displaying alphanumeric
figures. The AD300/MD300
instruments are equipped
with an electronic "watch
dog," which monitors the
circuitry within the unit for
potential faults and
renders the unit
inoperable until the
condition is corrected.
(See Watch dog section
below)
Several conditions can
activate the "watch dog."
Dropping the unit, poor
battery connections, and
radio frequency
interference are the
most common causes.
See the watch dog
section for additional
information
A) Disconnect the
batteries and inspect
the contacts for
corrosion. Reconnect
the batteries. If the
unit functions
properly, calibrate the
unit and reset the
alarm values.
B) Try a new set of
batteries.
C) Increase the distance
between the unit and
any source of radio
frequency
interference. The
sensor cable is a
prime source of
pickup as it can act
like an antenna.
Relocate the sensor
cable and if possible
change its coiled
length to ―de-tune‖ its
antenna effect.
Placing the cable in a
different position may
also help.
Alarm sounds/flashes
continuously. A) (MD300) Readings
are outside alarm
limits.
A) Adjust high and low
alarm setting to be
above and below O2
value being
displayed.
No display. A) Batteries expired.
B) Bad battery
connection.
A) Check/replace
batteries.
B) Check battery
connections.
C) Calibrate.
Keys inoperable/cannot
turn unit off The LOCK/UNLOCK key
is activated which is
preventing key operation
A) Press
LOCK/UNLOCK key
once. LCD will flash
indicating keys are
active.