Teledyne 300E Instruction Manual page 211

Model 300E Carbon Monoxide Analyzer
Instruction Manual
11.5.6.4. IR Source
The IR source can be checked using the following procedure:
1. Disconnect the source and check its resistance when cold. When new, the
source should have a cold resistance of more than 1.5 Ohms but less than
3.5 Ohms. If not, then the source is bad.
2. With the source disconnected, energize the analyzer and wait for it to start
operating. Measure the drive Voltage between pins 1 and 2 on the jack that
the source is normally connected to, it should be 11.5 ± 0.25 VDC. If not,
then there is a problem with either the wiring, the Relay Board, or the +12V
power supply.
3. If the drive voltage is correct in step 2, then remove the source from the
heat sink assembly (2 screws on top) and connect to its mating connector.
Observe the light being emitted from the source. It should be centered at
the bottom of the U-shaped element. If there is either no emission or a
badly centered emission then the source is bad.
11.5.6.5. Pressure/Flow Sensor Assembly
The pressure/flow sensor PCA (04003), located on the top of the absorption bench,
can be checked with a Voltmeter using the following procedure which, assumes that
the wiring is intact, and that the Motherboard and the power supplies are operating
properly:
1. For Pressure related problems:
Measure the voltage across C1 it should be 5 ± 0.25 VDC.
§
the board is bad.
Measure the voltage across TP4 and TP1. With the sample pump disabled
§
it should be 4500 mV ±250 mV. With the pump energized it should be
approximately 200 mV less. If not, then S1, the pressure transducer is
bad, the board is bad, or there is a pneumatic failure preventing the
pressure transducer from sensing the absorption cell pressure properly.
2. For flow related problems:
Measure the voltage across TP2 and TP1 it should be 10 ±0.25 VDC. If
§
not then the board is bad.
Measure the voltage across TP3 and TP1. With proper flow (800 sccm at
§
the sample inlet) this should be approximately 4.5V (this voltage will vary
with altitude). With flow stopped (sample inlet blocked) the voltage
should be approximately 1V. If the voltage is incorrect, the flow sensor
is bad, the board is bad or there is a leak upstream of the sensor.
P/N 04288 REV: A
TROUBLESHOOTING & REPAIR PROCEDURES
If not then
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