Teledyne 6200T - Sulfides Analyzer - Manual (Page 258)

Troubleshooting Model 6200T Total Sulfur Analyzer
258 Teledyne Analytical Instruments
 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.
12.6.14. High Voltage Power Supply
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
the supply. The second is the programming voltage which is generated on the Preamp
Board. This power supply is unlike a traditional PMT HVPS. It is like having 10
independent power supplies, one to each pin of the PMT. The test procedure below
allows you to test each supply.
1. Check the HVPS test function via the front panel and record the reading level.
Adjustment of the HVPS output level is covered in the hardware calibration
procedure in Section 12.7.2.8.
2. Turn off the instrument.
3. Remove the cover and disconnect the 2 connectors at the front of the PMT housing.
4. Remove the end plate from the PMT housing.
5. Remove the HVPS/PMT assembly from the cold block inside the sensor. Un-plug
the PMT.
6. Re-connect the 7 pin connector to the Sensor end cap, and power-up the
instrument.
7. Check the voltages between the pairs of pins listed in Table 12-9. The result for
each pair should be equal and approximately 10% of the reading level recorded in
Step 1.