1.Use alcohol pad to clean sector gear
2.Attach the sticker for gear on the bottom surface of sector gear (One of them is for 9:1 gear set，The rest 3 stickers are for 18:1, 13:1, 16:1 gear set)
3.Make sure the surface of gear sensor is clean and gear sensor is not obscured.
4.Before installing, please shim the gearbox first，make sure the sticker would not be interfered by spur gear.
5.Since the structure of AKA gearbox is different ，raised parts that have been circled by green box should be cut
6.AKA gearbox after modification.
7.In addition, the maximum angle of rotation of trigger is not enough to reach the trigger sensor for AKA gearbox. The limit for trigger should be modified. Cut the parts that are circled by green box and extend the slot of trigger.
8.Green line is the limit for trigger before modification and red line is the limit for trigger after modification.
9.For the gearbox V3 of other brands，there is no need for modification before installation.
10.Place the DTU V3 on the gearbox，then put the attached insulation washer on the screw hole before tighten the screw.
11.Then install the rest of parts into the gearbox. Attention, the material of moving element of trigger must not be transparent，Otherwise it needs to be painted black or it should be changed to an opaque one. While the trigger is pulled to the end, it needs to block the IR signal that is emitted by transmitter to receiver.
12.While the trigger was pulled to the end. The angle of element should follow the outline of circuit board，as the green line that has shown in the picture below. Otherwise, the slot for trigger should be extended more.
13.Place shims on the axel of this moving element properly to make sure there is no gap between it and left gearbox shell in case of light leak. As the green arrow shows.
14.Attach the sticker for selector on the outer side of selector plate，make sure it can cover the selector sensor while the selector plate is at ‘auto’ position （For G36, it is ‘Auto’;For AK47, it is ‘semi’. Then slide selector plate to ‘semi’ position (For G36, it is ‘semi’; For AK, it is ‘auto’), the sticker should not cover selector sensor at this position. It is recommended that the color of the surface of gearbox around selector plate and selector plate should be black or other dark color. Otherwise, paint them black.
The certain position of sticker is different for gearboxes from manufacturer ，it needs to be adjusted for few times until the selector is precious and clear.