Excessive Noise - Teledyne 300E Instruction Manual

Model 300E Carbon Monoxide Analyzer
Instruction Manual
2. Assuming that the I
the Relay board, the solid-state relay (K1) on the Relay Board (see Figure
10-2) may have failed. Using the WHEEL_HEATER parameter under the
Signal I/O function, as described above, turn on and off K1 (D2 on the relay
board should illuminate as the heater is turned on). Check the AC voltage
present between pin 1 and 4.
WARNING: Hazardous Voltages are present during this test
If the relay has failed there should be no change in the voltage across pins 1
and 4. Note, K1 is socketed for easy replacement.
3. If K1 checks out OK, the thermistor temperature sensor located at the front
of the filter wheel assembly may have failed. Unplug the connector labeled
"Wheel", and measure the resistance of the thermistor. The resistance near
the 68
11.4.1.4. IR Photo-Detector TEC Temperature
If the PHT DRIVE test parameter described above in Table 10-2 is out of range
there are two four possible causes of failure.
1. The screws retaining the IR photo detector to the Absorption Bench have
become loose. Carefully tighten the screws, hand-tight and note whether,
after the analyzer has come up to operating temperature, whether the PHT
DRIVE voltage has returned to an acceptable level.
2. The two large transistor-type devices mounted to the side of the Absorption
Bench have come loose from the bench. Tighten the retaining screws and
note whether there is an improvement in the PHT DRIVE voltage.
3. The photo-detector has failed. Contact the factory for instructions.
4. The Sync Demodulator circuit board has failed. Contact the factor for
instructions.

11.4.2. Excessive Noise

Noise is continuously monitored in the TEST functions as the STABIL reading and
only becomes meaningful after sampling a constant gas concentration for at least
10 minutes. Compare the current STABIL reading with that recorded at the time
of manufacture (included in the M300E Final Test and Validation Data sheet-p/n
04271 shipped with the unit from T-API).
1. The most common cause of excessive noise is leaks. Leak check and flow
check the instrument described in Section 9.5.
P/N 04288 REV: A
2
C bus is working and that there is no other failure with
o
C setpoint is ~5.7k ohms.
TROUBLESHOOTING & REPAIR PROCEDURES
205