Teledyne AX300-I Operating/Service Instructions Manual page 30

Service Instructions
Symptom
The oxygen reading
fluctuates or appears to
be incorrect.
The unit has stopped
working and the LCD is
displaying alphanumer-
ic characters.
No display.
Note: In the event that none of these procedures produces desired results, remove the
batteries and return the unit to Teledyne for repair.
Teledyne Analytical Instruments
Why
The sample pressure
may be changing.
The AX300-I unit is
equipped with an elec-
tronic "watch dog,"
which analyzes the
circuitry within the unit
for potential faults and
renders the unit in-
operable until the con-
dition is corrected. (See
Watch dog section)
Several conditions can
activate the "watch
dog." Dropping the unit,
poor battery connec-
tions, and radio fre-
quency interference are
the most common
causes. See the watch
dog section for addi-
tional information
A) Batteries expired.
B) Bad battery connec-
tion.
What To Do
A) During calibration, make
sure there is no restriction
on exhaust side of sensor. If
the reading changes with
flow, the sensor is pressu-
rized or there may be a leak
in the system.
B) If a high degree of accuracy
is desired, or the concentra-
tion of O2 being analyzed is
in excess of 40%, calibration
with 100% is recommended.
C) If humidified gas is used to
ventilate the patient, water
vapor actually dilutes the
gas. See Section 2.3. .
D) If a blender is used, check
its calibration.
A) Disconnect the batteries and
inspect the contacts for cor-
rosion. Reconnect the batte-
ries. If the unit functions
properly, calibrate the unit
and reset the alarm values.
B) Try a new set of batteries.
C) Increase the distance be-
tween the unit and any
source of radio frequency in-
terference. The sensor ca-
ble is a prime source of
pickup as it can act like an
antenna. Relocate the sen-
sor cable and if possible
change its coiled length to
"de-tune" its antenna effect.
Placing the cable in a differ-
ent position may also help.
A) Check/replace batteries.
B) Check battery connections.
C) Calibrate.
AX300-I
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