Teledyne 6400A - Sulfur dioxide analyzer - Manual (Page 120)

TAI Model 6400A SO
2
Analyzer Operator Manual, 02164, Rev. G
9-2
Check the TEST functions:
A. Compare the TEST functions to the factory values in Table 2-1. This will often provide
important clues as to the problem.
B. Check for the sign of the drift, particularly the slope and offset readings:
The slopes are the software equivalent of the span pot on an analog instrument. If the
slopes are not 1.0 ± 0.3, the gain has changed, usually from:
1) Possible causes for the drift or change of slope are;
a) PMT HVPS change
b) Incorrect span gas concentration
c) Pneumatic leak such as sample filter, pneumatic lines, kicker, reaction cell, etc.
d) UV lamp not calibrated
2) Possible causes for the drift or change of offset are;
a) Pneumatic leak
b) Light leak
c) UV filter damaged
d) Incorrect zero gas
Incorrect span gas concentration - this could come either from the calibrator or entering the expected
span gas concentration in the 6400A incorrectly, see Table 7-3.
4. If the instrument does not respond to span gas check Section 9.2.3.
The above should get you started in diagnosing and troubleshooting the most common faults. If
these reasons have been eliminated, the next thing to do is a Factory Calibration covered in
Section 9.1.6 or check Section 9.2 for other fault diagnosis. If difficulties persist contact our
service department. The 800 telephone number is on the cover page of this manual.