Advertisement
Troubleshooting
Troubleshooting Guides
6-6
Model 43i Trace Level-Enhanced Instruction Manual
Malfunction
Possible Cause
Detection circuit failure
Instrument is not properly
calibrated.
Input board malfunction
Signal cable failure
PMT failure
Flash lamp assembly
failure
Span calibration
Bad span gas
coefficient outside
acceptable limits of
0.5 – 2.0.
System leak
Insufficient calibrator flow
Excessive noise or
Defective or low
spikes on analog
sensitivity PMT
outputs
Defective input board or
BNC connection
Noise pick-up by recorder
or data logger
Poor linearity
Problem with calibrator
Action
Check all external plumbing and the
source of the sample to verify that the
SO
is not being adsorbed by the
2
sampling system. Lines carrying SO
must be made from clean Teflon or
stainless steel.
Go to Diagnostics menu and run the
optical span test to verify PMT and
associated electronics.
Go to the Calibration Factors menu and
verify that the SO
Background and SO
2
Coefficient are set appropriately.
Go to Service Menu and select Input
Board Test to verify A/D signal on each
range.
While viewing the Input Board Test
screen, set the gain to 100 and then
disconnect the signal cable from the
input board. The signal should drop
from a value above 1000 to near zero.
Check the PMT voltage (Service menu).
Check the lamp voltage (Service menu).
Verify quality of span gas.
Perform leak test.
Verify calibrator is providing a flow of at
least 0.8 LPM.
Check PMT voltage and run an optical
span test. Replace PMT with known
good unit if possible.
Identify the defective component and
replace.
Check analog cable shielding and
grounding.
Try to localize source of noise by
comparing analog signal to data
collected through RS-232 or Ethernet.
Verify accuracy of the multipoint
calibration system with an independent
flow meter.
Thermo Fisher Scientific
2
2
Advertisement
Troubleshooting
