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Preventive Maintenance
Monitoring Detector Frequencies and Noise
5-4
Model 49
i
Instruction Manual
Thermo Fisher Scientific
Monitoring Detector
Frequencies and
Noise
The Model 49
i
measures intensity ratios and not absolute values. Therefore,
a large range of detector frequencies are acceptable for proper operation of
the instrument. The nominal values are 65 to 120 kHz. These frequencies
can be monitored from the Intensities screen in the Diagnostics menu.
1. Press
to display the Main Menu.
2. Use
to scroll to Diagnostics, press
>
to
scroll to
Intensities
and press
.
The Intensities screen appears.
Degradation of detector frequencies to below 65 kHz indicates either a dirty
cell or low lamp output. In addition to degrading the measured detector
frequency, dirt in the cells can decompose the ozone and give erroneous
readings. Therefore, the cells should first be cleaned and the frequency
re-measured.
Increasing Lamp Output
If the frequencies are still low, the lamp output can be increased by using the
Lamp Setting screen in the Service mode. If the frequency cannot be set
above 65 kHz, replace the lamp.
1. Press
to display the Main Menu.
2. Use
to scroll to Service, press
>
to scroll to
Lamp Setting
and press
.
The Lamp Setting screen appears.
If the Service Mode is not displayed on the Main Menu, use the
following procedure to display it.
a. At the Main Menu, press
to scroll to Instrument Controls >
press
>
to scroll to
Service Mode
> and press
.
The Service Mode screen appears.
b. Press
to toggle the Service Mode to ON.
c. Press
>
to return to the Main Menu.
Monitoring Lamp Noise
To monitor the lamp noise, display Intensity Check from the Service mode
menu.
Summary of Contents for 49i
Page 1: ...Model 49i Instruction Manual UV Photometric O3 Analyzer Part number 102434 00 10Jan2008 ...
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Page 14: ...Contents xiv Model 49i Instruction Manual Thermo Fisher Scientific ...
Page 16: ...Figures xvi Model 49i Instruction Manual Thermo Fisher Scientific Flag Status B 11 ...
Page 36: ...Installation Startup 2 10 Model 49i Instruction Manual Thermo Fisher Scientific ...
Page 184: ...Troubleshooting Service Locations 6 22 Model 49i Instruction Manual Thermo Fisher Scientific ...