Philips CM12 manual Condenser Aperture Adjustment, Condenser Astigmatism Correction

Erwin Sabio Philips CM12 Alignment & Setup Manual Page 10

Condenser Aperture Adjustment

Figure 11 A non-concentric beam is seen when the condenser aperture is not aligned.

1.The condenser aperture controls the beam that passes through the condenser lens. If the aperture is not aligned, the beam will not spread concentrically on either side of the cross-over when the intensity knob is turned. Start aligning by spreading the beam on one direction past the crossover.

2.Adjust the knobs found on the condenser aperture assembly [2] until the beam becomes centered.

3.Spread the beam toward the other direction and adjust the condenser aperture knobs once more.

4.Repeat the above steps until the beam spreads concentrically on either direction past the cross-over.

Condenser Astigmatism Correction

1.Asymmetric magnetic fields around the condenser lens results in an unbalanced focus of the beam. This phenomenon is called astigmatism. When this happens, the beam spreads as asymmetric ellipses on either direction past the cross-over when the intensity knob is turned. Start correcting astigmatism by spreading the beam on one direction past the crossover.

Figure 12 Schematic of the symptom of condenser astigmatism

2.Press the STIG button found near the ALGN button shown in Figure 10 then select condenser from the menu that appears onscreen.

3.The STIG button once again activates the multifunction X/Y knobs. Use these to adjust the beam so that it becomes circular.

3.Spread the beam toward the other direction and adjust the multifunction X/Y knobs once more.

4.Press the STIG button once the astigmatism has been corrected to exit stigmation mode.