Instruction Manual
PD 300
10 TROUBLE SHOOTING GUIDE
Problem Cause
Solution
Press ‘ON’ key but no
display
a) Batteries not in place
b) Batteries not in correct polarity
(+ and – position).
c) Weak
batteries
a) Check that batteries are in place
and making good contact.
b) Re-insert batteries with correct
polarity.
c) Replace
batteries.
Not responding to key
press
a) HOLD mode in operation.
b) Damaged key pad.
c) Internal program error.
a)
Cancel HOLD mode by
pressing Hold key.
b)
Return to dealer.
c)
Reset all internal programs by
reinserting batteries.
Unstable readings
a)
Insufficient electrolyte in probe.
b)
Air bubbles in probe.
c)
Dirty probe.
d)
Probe not deep enough in
sample.
e)
External noise pickup or
induction caused by nearby
electric motor.
f)
Broken probe.
a)
Fill probe with reference
electrolyte.
b)
Tap probe to remove bubbles.
c)
Clean the probe and re-
calibrate.
d)
Make sure sample entirely
covers the probe sensors.
e)
Move or switch off interfering
motor.
f)
Replace probe.
“OR” or “UR” on
upper display
a) Probe is shorted.
b) Probe is in out-of-range (OR) or
under range (UR) condition.
c) Broken probe.
a)
Test probe. Make sure probe is
fully connected to meter.
b)
Use different solution.
c)
Replace probe. See
Accessories section.
Temperature reading
erratic or lower
display reads “OR”
a)
Temperature of solution is out
of range.
a)
Heat or cool solution.
Slow response
a)
Dirty / Oily probe.
a)
Clean probe. See Probe Care
& Maintenance section.
b)
Check membrane of DO probe.
Replace if necessary
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