Model 300E Carbon Monoxide Analyzer
Instruction Manual
TROUBLESHOOTING & REPAIR PROCEDURES
P/N 04288 REV: A
193
Test
Functions
(
As Displayed)
Indicated Failure(s)
BOX TEMP
If the Box Temperature is out of range, check fan in the Power Supply Module. Areas to the
side and rear of instrument should allow adequate ventilation. See Table 11-1 for
BOX
TEMP WARNING.
PHT DRIVE
If this drive voltage is out of range it may indicate one of several problems:
- A poor mechanical connection between the various components in inside the detector
housing
- An electronic failure of the IR Photo-Detector’s built-in cooling circuitry, or;
- A temperature problem inside the analyzer chassis. In this case other temperature
warnings would also be active such as
BENCH TEMP WARNING
or
BOX TEMP
WARNING
.
SLOPE
Values outside range indicate
§
Contamination of the Zero Air or Span Gas supply
§
Instrument is miss-calibrated
§
Blocked Gas Flow
§
Contaminated or leaking GFC Wheel (either chamber)
§
Faulty IR Photo-Detector
§
Faulty Sample Pressure Sensor (P1) or circuitry
§
Invalid M/R ratio (see above)
§
Bad/incorrect Span Gas concentration due.
OFFSET
Values outside range indicate
§
Contamination of the Zero Air supply
§
Contaminated or leaking GFC Wheel (either chamber)
§
Faulty IR Photo-Detector
11.1.3.
Using the Diagnostic Signal I/O Function
The Signal I/O parameters found under the DIAG Menu (see Section 7.4.1 and
Appendix A) combined with a thorough understanding of the instruments Theory of
operation (found in Section 10) are useful for troubleshooting in three ways:
§
The technician can view the raw, unprocessed signal level of the analyzer’s
critical inputs and outputs.
§
All of the components and functions that are normally under algorithmic
control of the CPU can be manually exercised.
§
The technician can directly control the signal level Analog and Digital Output
signals.
This allows the technician to systematically observe the effect of directly controlling
these signals on the operation of the analyzer. Below in Figure 11-2 is an example
of how to use the Signal I/O menu to view the raw voltage of an input signal or to
control the state of an output voltage or control signal. The specific parameter will
vary depending on the situation.