1) Open the Vitara control panel:
2) Open "Vitara Expert"
3) Ensure the diode has sufficient voltage. ~3.5 is good. If the number is green you're good.
If it reads 0.5V or -0.1V or something else odd check to make sure the Vitara is on and modelocked.
4) "Meas. Freq" should be 68 MHz +/- 50 kHz
If the Vitara has been off for a while, the Measured Frequency can be off by more than 50 kHz, but it generally doesn't wander that far.
5) Open "Freq Search Details"
6) Adjust oscillator cavity motor to get to 68 MHz +/- 50 Hz. Yes 50 hertz.
Roughly the cavity should change at a rate of -30.8 MHz/m. So a 1 um step will change the cavity by 30 Hz, 10 um by 308 Hz and 100 um by 3080 Hz. There is pretty annoying backlash when trying to move the motor by less than 10 um, so be patient.