Справочник Пользователя для Teledyne Camera Accessories T100

The photo multiplier tube detects the light emitted by the UV excited fluorescence of 
SO

2

. It has a gain of about 500000 to 1000000. It is not possible to test the detector 

outside of the instrument in the field. The best way to determine if the PMT is working 
properly is by using the optical test (OTEST), which is described in Section 5.9.4. The 
basic method to diagnose a PMT fault is to eliminate the other components using 
ETEST, OTEST and specific tests for other sub-assemblies. 

To check the correct operation of the preamplifier board, we suggest the technician carry 
out the electrical and optical tests described in 5.9.4 and 5.9.5.  

If the ETEST fails, the preamplifier board may be faulty. 

The TEC control printed circuit assembly is located on the sensor housing assembly, 
under the slanted shroud, next to the cooling fins and directly above the cooling fan.  

  If the red LED located on the top edge of this assembly is not glowing the control 

circuit is not receiving power.  

  Check the analyzer's power supply, the relay board’s power distribution circuitry 

and the wiring connecting them to the PMT temperature control PCA. 

12.6.13.1. TEC CONTROL TEST POINTS 

Four test points are also located at the top of this assembly they are numbered left to 
right start with the T1 point immediately to the right of the power status LED.  These 
test points provide information regarding the functioning of the control circuit. 

To determine the current running through the control circuit, measure the voltage 
between T1 and T2.  Multiply that voltage by 10. 

To determine the drive voltage being supplied by the control circuit to the TEC, measure 
the voltage between T2 and T3. 

  If this voltage is zero, the TEC circuitry is most likely open. 
  If the voltage between T2 and T3 = 0 VDC and the voltage measured between T1 

and T2 = 0 VDC there is most likely an open circuit or failed op amp on control 
PCA itself 

  If the voltage between T2 and T3 = 0 VDC and the voltage measured between T1 to 

T2 is some voltage other than 0 VDC, the TEC is most likely shorted 

T4 is tied directly to ground.  To determine the absolute voltage on any one of the other 
test points make a measurement between that test point and T4. 

The HVPS is located in the interior of the sensor module and is plugged into the PMT 
tube (refer to Figure 13-17). It requires 2 voltage inputs. The first is +15 which powers 

06807C DCN6650