Teledyne 400E - Using the Diagnostic Signal I;O Function; Table 11-2: Test Functions - Indicated Failures (Continued)

TROUBLESHOOTING & REPAIR PROCEDURES Model 400E Ozone Analyzer
Instruction Manual
248 P/N 04316 Rev: B
Table 11-2: Test Functions - Indicated Failures (Continued)
Test
Functions
(As Displayed)
Indicated Failure(s)
PRES
See Table 10-1 for SAMPLE PRES WARN.
SAMPLE FL Check for Gas Flow problems. See Section 11.2.
SAMPLE TEMP
Temperatures outside of the specified range or oscillating temperatures are
cause for concern.
PHOTO LAMP
TEMP
Bench temp control improves instrument noise, stability and drift. Temperatures
outside of the specified range or oscillating temperatures are cause for concern.
See Table 10-1 for PHOTO LAMP TEMP WARNING.
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 10-1 for BOX TEMP WARNING.
O3 GEN TEMP
If the O3 Generator Temperature is out of range, check O3 Generator heater
and temperature sensor. See Table 10-1 for O3 GEN TEMP WARNING.
SLOPE
Values outside range indicate:
§ Contamination of the Zero Air or Span Gas supply.
§ Instrument is miss-calibrated.
§ Blocked Gas Flow.
§ Faulty Sample Pressure Sensor (P1) or circuitry.
§ Bad/incorrect Span Gas concentration.
OFFSET
Values outside range indicate:
§ Contamination of the Zero Air supply.
11.1.3. Using the Diagnostic Signal I/O Function
The Signal I/O parameters found under the DIAG Menu 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. 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.