Troubleshooting
Troubleshooting Guides
Thermo Electron Corporation Model 42i Low Source Instruction Manual 6-3
Unstable NO or NO
2
source Replace.
Clogged capillaries Unplug power cord. Clean or
replace capillary.
Clogged sample air filter Replace filter element.
Excessive noise Defective or low sensitivity PMT Unplug power cord. Remove
PMT. Install known good
PMT. Plug in power cord.
Check performance.
Defective input board Replace board.
Defective cooler Check temperature (less
than
-2 °C at T
amb
= 25 °C).
Non-linear response Incorrect calibration source Verify accuracy of multipoint
calibration source gas.
Leak in sample probe line Check for variable dilution.
Excessive response
time
Partially blocked sample capillary Unplug power cord. Clean or
replace capillary.
Hang up/blockage in sample filter Change element.
Improper converter
operation
Questionable calibration gas Verify accuracy.
Converter temperature too high or
too low
Temperature should be
approximately 325 °C.
Low line voltage Check to see if line voltage
is within specifications.
Molybdenum consumed Replace Molybdenum
converter cartridge.
Table 6-2. Troubleshooting - Alarm Messages
Alarm Message Possible Cause Action
Alarm - Cooler Temp
High
Check fan operation Replace defective fan.
Check fan filter Clean or replace foam filter.
Cooler reads 80 °C Bad unit Replace cooler.
Cooler does not hold set point of -3
°C
Replace cooler –
thermoelectric module
inside cooler failed.
Table 6-1. Troubleshooting - General Guide, continued
Malfunction Possible Cause Action
To Next Page