Teledyne T200, Operation Manual, Page: 279 / 425

Teledyne API
– T200 NO/NO
2
/NO
X
Analyzer Operation Manual Troubleshooting & Service
277
PMT Housing End Plate
This is the entry to the PMT Exchange
PMT Preamp PCA
High voltage Power Supply
(HVPS)
PMT
PMT Cold Block
Connector to PMT
Pre Amp PCA
12V Power
Connector
Cooling Fan
Housing
TEC Driver PCA
PMT Heat Exchange Fins
Light from Reaction
Chamber shines
through hole in side
of Cold Block
Insulation Gasket
PMT Power Supply
& Aux. Signal
Connector
PMT Output
Connector
Thermo-Electric Cooler
(TEC)
PMT Temperature
Sensor (thermistor)
O-Test LED
Insertion point for
reaction cell assembly
Sensor Housing
Figure 12-9: T200 Sensor Assembly
6. Remove the two connectors on the PMT housing end plate facing towards the front
panel.
7. Remove the end plate itself (4 screws with plastic washers).
Note If the black PMT housing end plate for the Sensor Assembly is removed, ensure
to replace the 5 desiccant bags inside the housing.
8. Remove the desiccant bags from the PMT housing.
9. Unscrew the PMT assembly, which is held to the cold block by two plastic screws.
10. Discard the plastic screws and replace with new screws at the end of this procedure
(the threads get stripped easily and it is recommended to use new screws).
11. Along with the plate, slide out the optic test (O-Test) LED and the thermistor that
measures the PMT temperature.

Thermistor will be coated with a white, thermal conducting paste.

Do not contaminate the inside of the housing with this grease, as it may
contaminate the PMT glass tube on re-assembly.
12. Carefully take out the assembly consisting of the HVPS, the insulation gasket and
the PMT.
13. Change the PMT or the HVPS or both, clean the PMT glass tube with a clean, anti-
static wipe and do not touch it after cleaning.
06858E DCN7057