11. PVI Master Mode selector can be rotated left [RALT + V] and right [RALT + B]:
o “ОТКЛ” = Powers the PVI-800 off.
o “КВД” = Verification of entered data. This mode allows you to check a waypoint’s coordinate and other data without changing the active navigation mode or steerpoint.
o “ВВОД” = Edit waypoint. This function allows you to enter waypoint coordinates, wind conditions, and other data. To do so:
Select EDIT
Press “ППМ” and the small upper window will display the total number of waypoints currently stored.
Press 1 – 6 on the keypad to select the desired waypoint number and the current waypoint coordinates will be displayed.
Using the keypad, enter new coordinates for the selected waypoint. Note that you should indicate N/S or E/W prior to entering the coordinate. To make the coordinate positive, press the 0 key first; to make the coordinate negative, press the 1 key first. When set to negative, a “-“ symbol will appear left of the coordinate.
After the coordinate has been entered, press the ENTER button. Or, you may press CANCEL to clear the data on the display.
This is from the Ka-50 manual, it might help. It's page 137 by the way.