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RGA Operation with Filament Off
There are some situations where it is desirable to operate with the filament turned off, to detect ions
which are created by some other means in a vacuum system. There is a very simple modification
which can be made to do this. Please note that, while the filament will be off when this modification
is made, the focus plate, anode grid and repeller grid voltages will still be on. To make this
modification, proceed as follows:
1) Remove the top cover of the ECU (Electronic Control Unit).
2) In the schematics included in the manual, locate the schematic QMSE_B2. In the upper left
corner of the schematic locate the EMIT SET point. On the top circuit board this point can be
found at pin 10 of JP400.
3) Locate JP400. You can find pin 10 by counting from the end of the jumper which has one corner
cut at an angle. Starting from this corner, the pins along the same side are numbered 1, 3, |