Справочник Пользователя для Hitachi Microscope & Magnifier S-4800

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4.4.5    When Emission Current is not Set at Normal Value 
 
    When emission current is not set at a normal value when you applied HV, check the followings. 
 
(1) If emission current indicator is not zero but smaller than the value selected in the Set Ie to box 
in the HV control dialog window, check the value of Vext on the dialog window. 
If it is near the maximum (6.4kV) , and it is just after you made flashing, the FE tip may be the 
end of its life. Contact a service engineer.   
If it is long after flashing, carry out flashing again. 
 
(2) If emission current reading is zero and a time-out error occurs at HV On operation, there may 
be some troubles on the FE tip or the high voltage power supply.    Contact a service engineer. 
 CAUTION 
 
Beware of 
electric shock
 
  Voltages up to 100 V AC and 30 kV DC are used in this 
instrument.    Touching the interior could cause an 
electric shock. 
  Never remove the covers of main unit, control unit or 
power unit and touch internal parts or circuits while 
power is connected to the instrument.    There is a 
danger of fatal or serious injury due to electric shock. 
  Do not detach the covers of the instrument. 
4.4.6    When Image is not Shown on Screen 
 
If you do not observe image on the image screen or difficult to focus the image, check the 
followings. 
 
(1) Check if a specimen is set normally, HV is on and emission current is about normal value, the 
gun valve is open, SE signal is selected, 1st condenser lens is set at 5, magnification is set at 
lowest and scan is running. 
 
(2) Set contrast at maximum. 
 
(3) Open the Alignment dialog window and start Beam Alignment mode.    If a circular image 
appears at out of the center of screen, carry out column alignment. 
 
(4) Open the Alignment dialog window and start Beam Alignment mode.    Set the beam monitor 
and the objective lens aperture at 0.    If a circular image appears, carry out column alignment. 
 
(5) If you can not fix the trouble by checking above, contact a service engineer.