Teledyne 6200T - Sulfides Analyzer - Manual (Page 274)

Troubleshooting Model 6200T Total Sulfur Analyzer
274 Teledyne Analytical Instruments
11. If the cold block or TEC is to be changed disconnect the TEC driver board from the
preamplifier board.
 Remove the cooler fan duct (4 screws on its side) including the driver
board.
 Disconnect the driver board from the TEC and set the sub-assembly aside.
 Remove the end plate with the cooling fins (4 screws) and slide out the
PMT cold block assembly, which contains the TEC.
 Unscrew the TEC from the cooling fins and the cold block and replace it
with a new unit.
12. Re-assemble the TEC subassembly in reverse order.
ATTENTION COULD DAMAGE INSTRUMENT AND VOID WARRANTY
The thermo-electric cooler needs to be mounted flat to the heat sink. If
there is any significant gap, the TEC might burn out. Ensure to apply heat
sink paste before mounting it and tighten the screws evenly and cross-
wise.
 Ensure to use thermal grease between TEC and cooling fins as well as
between TEC and cold block.
 Align the side opening in the cold block with the hole in the PMT housing
where the sample Chamber attaches.
 Evenly tighten the long mounting screws for good thermal conductivity.
13. Re-insert the TEC subassembly. Ensure that the O-ring is placed properly and the
assembly is tightened evenly.
14. Re-insert the PMT/HVPS subassembly.
 Don’t forget the gasket between HVPS and PMT.
 Use new plastic screws to mount the PMT assembly on the PMT cold
block.
15. Insert the LED and thermistor into the cold block.
16. Replace the desiccant bags with five new desiccant bags.
17. Carefully replace the end plate.
 Ensure that the O-ring is properly in place. Improperly placed O-rings will
cause leaks, which – in turn – cause moisture to condense on the inside of
the cooler causing the HVPS to short out.
18. Reconnect the cables and the reaction cell
 Be sure to tighten these screws evenly.
19. Replace the sensor assembly into the chassis and fasten with four screws and
washers.
20. Perform a leak check the system.
21. Power up the analyzer and verify the basic operation of the analyzer using the
ETEST and OTEST features (refer to Section 6.9.5 and 6.9.6) or by measuring
calibrated zero and span gases.