Biosystems EX CHEK Reference Manual - page 28
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6.3
Specific problems
6.3.1 Unit will not turn on
Possible causes:
Battery discharged, microprocessor /
software malfunction.
Solution(s):
Take the instrument to a non-hazardous
location. Recharge the batteries and
attempt to turn on. If the instrument still
fails to turn on, return to factory for repair.
6.3.2 Unit will not turn off
Possible causes:
Microprocessor / software malfunction,
low or bad battery, faulty on / off mode
switch.
Solution(s):
Take the instrument to a non-hazardous
location, replace the batteries, and
attempt to turn the detector back on. If
the instrument fails to turn on, return to
factory for repair.
6.3.3 Unstable sensor readings
Possible causes:
Loose connection, bad sensor, improper
calibration, expired calibration gas.
Solution(s):
Check that the sensor is firmly in place.
Check calibration gas dating. Recalibrate
sensor. Replace sensor if necessary.
6.3.4 Blank display
Possible causes:
Battery voltage too low. Operating
temperature too low. Bad LCD display
assembly. Microprocessor locked-up or
"crashed".
Solution(s):
Take the instrument to a non-hazardous
location. If cold, allow instrument to warm
back up to room temperature. Recharge
the batteries and attempt to turn the
instrument back on. If the instrument still
fails to turn on, return to factory for repair.
6.3.5 No audible alarm
Possible causes:
Loose connection, alarm failure.
Solution(s):
Return to factory for repair.
6.3.6 Keypad buttons (+,-, Cal, Alarm)
don't work
Possible causes:
Not in Technician mode, microprocessor
locked-up or "crashed", loose connection,
switch failure.
Solution(s)
Switch to Technician operating mode.
Take the instrument to a non-hazardous
location. Replace the batteries and
attempt to turn the instrument back on.
If keypad buttons still fail to operate
properly return to factory for repair.
6.3.7 Can’t make a “One Button” auto
zero adjustment (“Too High” or
“Too Low” for zero adjust)
Possible causes:
The atmosphere in which the instrument
is located is contaminated (or was
contaminated at the time the instrument
was last zeroed); instrument is still
attached to calibration fittings; a new
sensor has just been installed; instrument
has been dropped or banged since last
turned on.
Solution(s):
Remove any calibration gas fittings, take
the instrument to fresh air and allow
readings to stabilize. Do a manual fresh
air zero adjustment using buttons on the
instrument keypad as discussed in
Section 3.5.1.