7000A "Black Level to High" when using SAV aperture.
Several things can be done to try to resolve this issue. 1) Clean the lens and mirror make sure the aperture plate is snug and test. 2) Remove excess barium from SAV aperture with a dry q-tip swab and test. 3) Set the lense to VSA setting and calibrate with the SAV aperture.
Note: If there is still an issue there may be an allignment issue. In this case it will have to come in for a re-allignment.