Topcon GPT-2006 User Manual

   17 CHECK AND ADJUSTMENT

17-5

Adjustment is required if the axis of the plate level is not perpendicular to the vertical axis.

●

1) Place the plate level parallel to a line running through the centers of two leveling screws, say, A and 

B.  Use these two leveling screws only and place the bubble in the center of the plate level.  

2) Rotate the instrument 180° or 200g around the vertical axis and check bubble movement of the 

plate level.  If the bubble has been displaced, then proceed with the following adjustment.

●

1) Adjust the level adjustment capstan screw, with the accessory adjusting pin and return the bubble 

towards the center of the plate level.  Correct only one-half of the displacement by this method.

2) Correct the remaining amount of the bubble displacement with the leveling screws.
3) Rotate the instrument 180° or 200g around the vertical axis once more and check bubble 

movement.  If the bubble is still displaced, then repeat the adjustment.

Adjustment is required if the axis of the circular level is also not perpendicular to the vertical axis.

●

1) Carefully level the instrument with the plate level only.  If the bubble of the circular level is centered 

properly, adjustment is not required.  Otherwise, proceed with the following adjustment.

●

1) Shift the bubble to the center of the circular level, by adjusting three capstan adjustment screws on 

the bottom surface of the circular level, with the accessory adjusting pin.

Leveling screw 

Plate level

Leveling screw B

Level adjustment 
capstan screw

Half amount of displacement 

Total amount of displacement 

Capstan adjustment
screws

Bottom of the base

Circular level