The Grand Master inhibits the intensities of all fixtures on the console, including those within the Programmer. Parked intensities are NOT effected by the Grand Master level.
Since the Nano Hog 4, Road Hog 4, and HedgeHog 4 consoles do not have a dedicated Grand Master fader, master 1 is utilized as the grand master. However, it is still possible to assign a cuelist or scene to master 1 which will cover the grandmaster portion of the playback bar in which case master 1 and it's corresponding fader and buttons will no longer act as a control for the Grand Master but rather as a control for the cuelist or scene assigned to master 1. In this case the grandmaster can be accessed by holding down the GM key.
The GM key's red LED indicates the state of the Grand Master:
Off: Grand Master fader is at 100%
On: Grand Master fader is at 0%
Slow flashing: Grand Master fader is between 1% and 99%
Fast flashing: DBO is engaged
When the GM key is used in conjunction with master 1 on the console, it is possible for the position of master 1's physical fader to be different from the Grand Master's actual level. If this happens, then when the GM key is held down the Grand Master's level will be shown using a blue bar and the level of master 1's physical fader shown as a small red line. To recapture the Grand Master's level with the physical fader, move the physical fader until it is at the same level as the blue bar; at this point the fader will take control of the Grand Master level in the normal way.
Holding the PIG key while pressing the GM key acts as a virtual DBO key. When DBO is engaged the red LED on the GM key will flash quickly, the playback bar will display DBO in blue text, all intensity output will go to 0% (with the exception of parked values), and the grand master's fader level will be ignored.
The DBO key is located above the Grand Master on the Hog 4 and Full Boar 4 consoles and can be used to toggle the show between dead blackout and using the grand master's level.
The DBO key's red LED indicates it's status:
Off: DBO is not engaged and Grandmaster fader has control.
Fast Flashing: DBO is engaged and all fixture intensities will be restricted to 0% with the exception of parked intensities. When the DBO key is disenaged its red LED will turn off and the Grandmaster fader will regain control.
Road Hog 4, HedgeHog 4, and Nano Hog 4 do not have a dedicated DBO key, however the DBO can still be engadged/disengaged by holding pig and pressing the GM key.
The Flash key below the Grand Master fader is a non-latching key that can be assigned in the user preferences window to send the grand master's level to zero, to full, or to whichever value is opposing the grandmaster's current fader position.
The flash key below the grandmaster indicates the state of the Grand Master using its red LED:
Off: Grand Master is at 100%.
Fast Flashing: Grand Master fader is below 100%