Teledyne 6200T - Sulfides Analyzer - Manual (Page 260)

Troubleshooting Model 6200T Total Sulfur Analyzer
260 Teledyne Analytical Instruments
option is enabled if the TEST functions show a parameter named IZS
TEMP.
The IZS option is heated with a proportional heater circuit and the temperature is
maintained at 50° C ±1°. Check the IZS TEMP function via front panel display (refer to
Section 4.1.1) and the IZS_TEMP signal voltage using the SIGNAL I/O function
under the DIAG Menu (refer to Section 5.9.1).
At 50°
C, the temperature signal from the IZS thermistor should be around 2500 mV.
12.6.18. Box Temperature
The box temperature sensor (thermistor) is mounted on the motherboard at the bottom,
right corner of the CPU board when looking at it from the front. It cannot be
disconnected to check its resistance. Box temperature will vary with, but will always
read about 5° C higher than, ambient (room) temperature because of the internal heating
zones sample chamber and other devices.
To check the box temperature functionality, we recommend checking the BOX_TEMP
signal voltage using the SIGNAL I/O function under the DIAG Menu (refer to Section
5.9.1).
At about 30°
C (5  above typical room temperature), the signal should be around 1500
mV. We recommend using a certified or calibrated external thermometer / temperature
sensor to verify the accuracy of the box temperature.
12.6.19. PMT Temperature
PMT temperature should be low and constant. It is more important that this temperature
is maintained constant than it is to maintain it low. The PMT cooler uses a Peltier,
thermo-electric element powered by 12 VDC from the switching power supply PS2. The
temperature is controlled by a proportional temperature controller located on the
preamplifier board. Voltages applied to the cooler element vary from +/- 0.1 to +/- 12
VDC. The temperature set point (hard-wired into the preamplifier board) will vary by
about ±1
 C due to component tolerances. The actual temperature will be maintained to
within 0.1  C around that set point.
On power-up of the analyzer, the front panel enables the user to watch that temperature
drop from about ambient temperature down to its set point of 6-8° C.
 If the temperature fails to drop after 20 minutes, there is a problem in the
cooler circuit.
 If the control circuit on the preamplifier board is faulty, a temperature of -1
C is reported.