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Teledyne API – Model T300/T300M CO Analyzer Troubleshooting and Service
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12.5.7. SENSOR ASSEMBLY
12.5.7.1. SYNC/DEMODULATOR ASSEMBLY
To verify that the Sync/Demodulator Assembly is working, follow the procedure below:
1. Verify that D1 and D2 are flashing.
If not, check the opto pickup assembly, Section 12.5.7.3 and the GFC Wheel
drive, Section 12.5.7.4.
If the wheel d
rive and opto pickup are working properly then verify that there is
2.4 ±0.1 VAC and 2.5 ±0.15 VDC between digital ground and TP 5 on the
sync/demod board. If not then check the wiring between the sync/demod and
opto pickup assembly (see interconnect drawing, P/N 04216). If good then the
sync/demod board is bad.
2. Verify that the IR source is operating, Section 12.5.7.5.
3.
With the anal
yzer connected to zero air, measure between TP11 (measure) and
analog ground, and TP12 (reference) and analog ground.
If they are similar to values recorded on the factory data sheet then there is likely
a problem with the wiring or the A/D converter.
If they are not then either the sync demodulator board or the IR-photodetector are
bad. See Section 12.4.1.4 for problems with the IR-p
hotodete
ctor TEC drive.
12.5.7.2. ELECTRICAL TEST
The electric test function substitutes simulated signals for CO MEAS and CO REF,
generated by circuitry on the sync/demod board, for the output of the IR photo-detector.
While in this mode the user can also view the same test functions viewable from the
main SAMPLE display. When the test is running, the concentration reported on the
front panel display should be 40.0 ppm. Also see Section 5.9.4.
06864B DCN6314