GE MOA 280i, Руководство по эксплуатации и обслуживанию

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GE Analytical Instruments ©2006
15-11
DLM 14291 Rev. A
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Press ENTER or CLEAR to return to the Main Menu, select Analysis and Start.
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When the Startup Screen is displayed, press Enter to display the Status Screen.
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The NOA will turn on the high voltage to the PMT and display the PMT signal
(counts at analog-to-digital converter) in the Status Screen. Typically, the PMT
signal will be 10 – 50 counts and should always be < 100 counts. If there is a
light leak, the PMT signal will be higher than normal and the NOA may fail the
PMT test.
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If the signal is higher than normal, turn off the room lights and see if the PMT
signal decreases. If tuning the lights off does not change the PMT signal, then
there is not a light leak.
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If the PMT signal does change when the lights are turned off, try tightening the
Allen screws 1/2 to 1 turn and repeat the lights on/off test.
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If there is still a light leak after tightening the Allen screws, turn off the NOA,
remove the top cover, remove the PMT and check the o-rings in the reaction
cell. Reconnect the cooler to the reaction cell, install the PMT and top cover
and repeat the light-leak test.
Cooler Maintenance
Over time, the cooler will pick up water from the atmosphere that reduces its
efficiency. After one year of operation, it is necessary to remove the cooler from
the NOA and use an oven to remove water that has accumulated in the insulation.
To bake-out the cooler:
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Turn off the main power switch and remove the NOA top cover.
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Follow the procedures described above to remove the PMT and socket from the
cooler and to disconnect the cooler from the reaction cell. Remove the optical
filter from the cooler face.
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Slide the cooler all the way towards the front and the NOA.
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There are three electrical connections to the cooler: the fan power, power to
the cooler and the thermocouple. The fan connector is located on the left side
of the NOA as viewed from the front. Trace the wires from the fan to a small