8
advised to have the lamps changed. Deuterium and Tungsten lamps may be replaced by the
user. Xenon lamp replacement can only be carried out by a qualified service engineer.
To replace a Deuterium or Tungsten lamp ;
o
Switch the instrument off, disconnect the power supply cord and allow lamps to cool.
o
Locate the lamp access cover at the rear of unit and remove the two top screws and slide
top cover back and lift off. Never operate the unit with the lamp housing cover removed.
o
Remove the lamp and dispose of in accordance with local regulatory practice.
o
Follow the handling instructions supplied with the lamp. Do not touch the glass envelopes
of the replacement bulbs directly.
o
Replace the lamp cover and screw securely.
o
Attach power cord, switch on and wait at least 30 minutes for the unit to warm up.
o
Perform a new instrument baseline (on all bandwidth settings if variable bandwidth unit)
and save this as the permanent baseline (see the online help or user manual).
o
Reset the lamp hours after replacing the lamp (see the online help or user manual).
TROUBLESHOOTING
PROBLEM
POSSIBLE CAUSE
Start up calibration fails
Check sample (and reference) beam is clear before switch on
Possible optical failure, contact service support
Negative absorbance reading
Check that sample and reference cells have not been swapped
Check sufficient height of sample solution (beam height is
nominally 15 mm
above the cell base for normal measurements and it is
recommended that it be filled to 20 mm above the base)
Unexpected results
Check for bubbles in solution
Absorbance values higher than
expected
Check for use of incorrect cell type
Check cells are free from finger prints
Check cells for contamination
Check cell orientation
Check reference used
Possible optical alignment problem, contact service support
Absorbance value lower than
expected
Check sufficient height of sample solution
Check sample and reference are not the same
Check sample compartment lid is properly closed
Possible stray light issue, contact service support
Instrument will not reference
Check orientation of cuvette
Check for use of incorrect cell type
Poor reproducibility with
nucleic acid analysis
Check for particles, try using background correction
Try increase in concentration
