Condenser Lens Aperture Replacement - Hitachi TM3000 Instruction Manual

5.3 Condenser lens Aperture Replacement

The condenser lens aperture is built into the liner tube and it is located underneath the anode.
After the system has been in use for about 6 months and it appears that there is image
deterioration (an out-of-focus condition), replace the condenser lens aperture. When
replacing the condenser lens aperture, it is recommended that the objective aperture be also
replaced at the same time.
1. Introduce air into the specimen chamber.
Close the application program, and press the [EVAC/AIR] button to introduce air into the
specimen chamber.
2. When the blue LED lights up as shown in Figure 5.2-1, it is an indication that the
evacuation is complete; turn off the power switch.
CAUTION : If the system was in use until immediately before the cover was opened,
the Wehnelt and the anode around the filament could still be hot. To
avoid burns from touching it, perform filament replacement work by
allowing a minimum of 30 minutes after the power switch was turned off.
3. Wait for a minimum of 30 minutes, and then open the top cover. Holding onto the lower
part of the top cover with your finger tips, gently lift it.
4. There is a rubber cushion on the left side of the electron gun. Tilt the electron gun to the
left side of the system until it touches the cushion, and then gradually open the electron gun,
as shown in Figure 5.3-1.
The anode has a screw-in structure. Put on gloves, and remove the anode by turning it
counterclockwise. Cove the removed anode with clean aluminum foil or place it in a vinyl bag
to protect it from particles or scratches.
Cushion
Figure 5.3-1
Opening and Closing the Electron Gun
Figure5.3-2 Removing the Anode
5 - 19