Great Plains NTA3007HD Operator Manual - Manual (Page 85)

Adjustments 81
04/04/2011 166-207M
19. Refer to the seed rate chart for Seed Rate gearbox
setting values for the new chart rate.
Null4:
20. Adjust the control arm to the Gearbox Setting closest
to the NewChart rate.
21. Run the calibration again, starting at step 9, using
the new Variable Rate Gearbox scale setting.
This validates the gearbox adjustment, and estab-
lishes a new, more precise Calibration Constant.
22. With the present meter satisfactorily calibrated, re-
mount the final drive gear removed from the other
hopper.
23. Repeat the calibration procedure for the other hop-
per, starting at step 1.
24. Remove and store the calibration crank.
Contact Drive Adjustment
Refer to Figure 86 and Figure 87
There are two contract drive tension springs
on each
side of the drill; four total. If there seems to be:
• insufficient traction between the contact drive tires
and the main transport tires ;
• excess spring force at contact tires, or
• or a contact drive shaft is below the minimum clear-
ance when raised in the frame slots ,
then follow these steps:
1. Check tire size and inflation (page 145).
Use tire sizes specified by Great Plains, at recom-
mended pressures. The remaining steps of this sec-
tion cannot be used to compensate for incorrect
sizes and/or inflation.
49.2 31 77260 158.5 177.6 58
52.7 32 77341 163.7 183.5 59
56.3 33 77413 169.0 189.4 60
60.0 34 77479 174.3 195.4 61
63.7 35 77538 179.6 201.3 62
Example:
NewChart rate to use:
183.5
New Gearbox Setting:
59
Note: The rate of the arm adjusting crank is more than
one scale degree per turn, and the crank can only
be pinned at quarter turns. Pin it when the indica-
tor is closest to the desired setting.
Null4:
Figure 86
Contact Drive Springs
29591
2
7
3
6
1
1
2
3
4
5