MacDon FD75 OM - Manual (Page 74)

OPERATION
4. Fully lower the combine feeder house and float the
header up off the down stops (float indicator should be
on 4 and the adapter should be fully separated from
the header).
NOTE:
You may need to hold the header down switch
for a few seconds to ensure the feeder house is
entirely down.
5. Using a voltmeter (A), measure the voltage between
the ground and signal wires at the Auto Header Height
sensor in the float indicator box. It should be at the low
voltage limit for the combine, Refer to
Height Sensor
Output Voltage Range – Combine Requirements, page
58
.
6. If the sensor voltage is not within the low and high
limits, Refer to
Height Sensor Output Voltage Range
– Combine Requirements, page 58 , or if the range
between the low and high limits is insufficient, you
need to make adjustments. Refer to
Adjusting Voltage
Limits, page 60 for instructions.
Figure 4.37: Measuring Voltage Between
Ground and Signal Wires with a Voltmeter
Adjusting Voltage Limits
Procedure for adjusting voltage limits.
NOTE:
The sensor assemblies used with Lexion and some New Holland combines are slightly different from the
sensor assemblies used with other combine models. All three assemblies are illustrated here.
1. To adjust high voltage limit, follow these steps:
a. Fully extend guard angle; the header angle
indicator should be at D.
b. Position header 6–10 in. above the ground; the
float indicator should be at 0.
c. Loosen sensor mounting bolts (A).
d. Slide sensor support (B) to the right to increase the
high voltage limit and to the left to decrease it.
e. Tighten sensor mounting bolts (A).
Figure 4.38: Auto Header Height Sensor
Assembly for Use with Lexion Combines
169894 60 Revision A