SEM Contrast Problem

• System working normally, then SEM went dark on return from spot mode. 
• Contrast control has no effect. 
• In lens detector no signal
• SE2 detector turns on and off when selected, but SEM software does not control voltage. Good image with manual control.
• Image from Auger detector is good, beam hits sample.
• Exit SmartSEM, restart windows, restart SmartSEM, still broken.

Suspect SmartSEM programing voltage for CEM failed. Fuse??

Check voltages.

Brightness is +2.6 V for 100%, 0 for 50%, -2.6 for 0%, both SED and InLens. This seems right.

(pin to right of center in audio plug)

Contrast (center pin) is stuck at 1.92 V for SED and between 0.51 and 0.74 V (non linear) for InLens

Both should be 0 to +5 V for for 0 to 100%.

HV Monitor on Supra is +1.227 V for 100%, 0.314 for 25%.

On InLens is +0.018 V. 

work around

still no news from Omicron 11/8/12

Run SED in local mode, works, but must remember to shut down if not required, for sputter, etc. Also no brightness control.

Modify InLens, open housing, disconnect voltage monitor wire and use BNC for external brightness control. Write external LabView app to control voltage.