Figure 11-7: M200E Sensor Assembly - Teledyne 200E Instruction Manual

Troubleshooting & Repair
• Unscrew the PMT assembly, which is held to the cold block by two plastic screws.
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).
• Carefully take out the assembly consisting of the HVPS, the gasket and the PMT.
• 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.
• 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.
• Re-assemble this TEC subassembly in reverse order. Make sure to use thermal
grease between TEC and cooling fins as well as between TEC and cold block and that
the side opening in the cold block will face the reaction cell when assembled. Evenly
tighten the long mounting screws for good thermal conductivity.
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Figure 1 -7: M200E Sensor Assembly 1
Model 200E Instruction Manual
044100102 Rev A