Teledyne MODEL T703 Manual Do Utilizador

Individual control loops are used to maintain the set point of the UV lamp and ozone generator.  If any of these 
temperatures are out of range or are poorly controlled, the T703 will perform poorly.  

 

The box temperature sensor is mounted to the motherboard and cannot be disconnected to check its resistance.  
Rather check the BOX TEMP signal using the SIGNAL I/O function under the DIAG Menu (see Section 11.1.3).  
This parameter will vary with ambient temperature, but at ~30

o

C (6-7

 above room temperature) the signal 

should be ~1450 mV.  

 

The temperature of the gas in the photometer sample chamber should read approximately 5.0

C higher than the 

box temperature. 

 

There are three possible causes for the UV Lamp temperature to have failed. 

  The UV Lamp heater has failed.  Check the resistance between pins 5 and 6 on the six-pin connector 

adjacent to the UV Lamp on the Optical Bench.  

  It should be approximately 30 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 PHOTO_LAMP HEATER parameter under the SIGNAL I/O function of the DIAG menu, as 

described above, turn on and off the UV Lamp Heater (D15 on the relay board should illuminate as 
the heater is turned on).  

  Check the DC voltage present between pin 1 and 2 on J13 of the Relay Board.  
  If the FET Driver has failed, there will be no change in the voltage across pins 1 and 2.  

  If the FET Driver Q2 checks out OK, the thermistor temperature sensor in the lamp assembly may have 

failed.  

  Unplug the connector to the UV Lamp Heater/Thermistor PCB, and measure the resistance of the 

thermistor between pins 5 and 6 of the 6-pin connector.  

  The resistance near the 58

o

C set point is ~8.1k ohms.  

07223B DCN6378