Teledyne 6200E - Sulfides Analyzer - Manual (Page 259)

Model 6200E Instruction Manual TROUBLESHOOTING & REPAIR
M6200E Rev: A1 259
11.5.12. PMT Preamplifier Board
To check the correct operation of the preamplifier board, we suggest the technician carry out the
electrical and optical tests described in 6.8.5. and 6.8.6. If the ETEST fails, the preamplifier board
may be faulty.
11.5.13. PMT Temperature Control PCA
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 analyzers power supply, the Relay boards power distribution circuitry
and the wiring connecting them to the PMT temperature control PCA.
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.
Or,
• 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 ant T4.