Teledyne M300EM User Manual

13.5.6. SENSOR ASSEMBLY 

13.5.6.1. 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 13.5.6.3 and the GFC Wheel drive, Section 13.5.6.4. 
  If the wheel drive 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 13.5.6.5. 
3.  With the analyzer 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 

13.4.1.4 for problems with the IR-photodetector TEC drive. 

 

13.5.6.2. 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. (See Section 9.6.4 to calibrate Electrical Test). 

 

04288D DCN5752