Teledyne T703U VCR User Manual


 
General Troubleshooting & Service Teledyne API T703/T703U Calibrator Operation Manual
184
8.4.12.4. Ozone Generator Temperature
There are three possible causes for the Ozone Generator temperature to have failed.
The O
3
generator heater has failed. Check the resistance between pins 5 and 6 on
the 6-pin connector adjacent to the UV Lamp on the O
3
Generator. It should be
approximately 5 Ohms.
Assuming that the I
2
C bus is working and that there is no other failure with the Relay
board, the FET Driver on the Relay Board may have failed. Using the
O3_GEN_HEATER parameter under the SIGNAL I/O function of the DIAG menu,
as described above, turn on and off the UV Lamp Heater. Check the DC voltage
present between pin 1 and 2 on J14 of the Relay Board.
If the FET Driver has failed, there should be no change in the voltage across pins 1
and 2.
If the FET Driver checks out OK, the thermistor temperature sensor in the lamp
assembly may have failed. Unplug the connector to the Ozone Generator
Heater/Thermistor PCB, and measure the resistance of the thermistor between pins
5 and 6 of the 6-pin connector.
8.5. TROUBLESHOOTING THE O
3
PHOTOMETER
8.5.1. DYNAMIC PROBLEMS WITH THE O
3
PHOTOMETER
Dynamic problems are problems, which only manifest themselves when the photometer
is measuring O
3
concentration gas mixtures. These can be the most difficult and time
consuming to isolate and resolve.
Since many photometer behaviors that appear to be a dynamic in nature are often a
symptom of a seemingly unrelated static problems, it is recommended that dynamic
problems not be addressed until all static problems, warning conditions and subsystems
have been checked and any problems found are resolved.
Once this has been accomplished, the following most common dynamic problems
should be checked.
8.5.1.1. Noisy or Unstable O
3
Readings at Zero
Check for leaks in the pneumatic system as described in Section 7.2
Confirm that the Zero gas is free of Ozone.
Confirm that the Source Lamp is fully inserted and that the lamp hold-down thumb-
screw is tight.
Check for a dirty Absorption Cell and/or pneumatic lines. Clean as necessary as
described in Section 7.2
Disco
nnect the exhaust line from the optical bench (the pneumatic line at the lamp
end of the bench) and plug the port in the bench. If readings remain noisy, the
problem is in one of the electronic sections of the instrument. If readings become
quiet, the problem is in the instrument's pneumatics.
07223C DCN6572