YSI 550A - Manual (Page 16)

Page 12
Y S I
Environmental
YSI 550A
TROUBLESHOOTING
NOTE: An error displayed briefly during the first few seconds after turning the instrument
on does NOT indicate a problem.
SYMPTOM POSSIBLE SOLUTION
1. Instrument will not turn on,
LCD displays "LO BAT", or
Main display flashes “OFF”
A. Low battery voltage, replace batteries
B. Batteries installed incorrectly, check battery polarity
C. Return system for service
2. Instrument will not calibrate. A. Replace membrane and electrolyte
B. Clean probe electrodes
C. Return system for service
3. Instrument "locks up". A. Remove batteries, wait 15 seconds for reset, replace batteries
B. Replace batteries
C. Return system for service
4. Instrument readings are
inaccurate.
A. Verify calibration altitude and salinity settings are correct and
recalibrate.
B. Probe may not have been in 100% water saturated air during
calibration procedure. Moisten sponge in calibration chamber
and recalibrate.
C. Replace membrane and electrolyte. Recalibrate.
D. Clean probe electrodes.
E. Return system for service.
5. Main display reads “Over” or
“Undr”.
A. Sample O
2
concentration is more than 60 mg/L or 500%, or
less than –0.02 mg/L or -0.3%.
B. Verify calibration altitude and salinity settings are correct and
recalibrate.
C. Replace membrane and electrolyte. Recalibrate.
D. Clean probe electrodes.
E. Return system for service.
6. Main display reads “Over” or
“Undr” during calibration.
A. Replace membrane and electrolyte. Recalibrate.
B. Clean probe electrodes.
C. Return system for service.
7. Secondary display reads
"Ovr" or “Undr”.
A. Sample temperature is less than -5º C (23ºF) or more than
+45 o C (122 o F). Increase or decrease the sample temperature to
bring within the allowable range.
B. Return system for service.