If all other methods for moving the ADC fail, there is a last
ditch procedure to attempt to move the prism cells into the
Null position. There is a Bypass Mode Switch that is also
mounted on the front panel of the electronics box (see picutre
Figure 1: ADC electronics rack.
The adc electronics box is located in the HIRES valut.
Please see EL-3612:6 "Interlock wiring, bypass and emergency stop wiring details" in the electronics manual for more documentation about the bypass switch.