Adjusting Voltage Limits - MacDon FD75 Operator's Manual

3. Measure voltage between ground and signal wires at
AHHC sensor in float indicator with a voltmeter (A).
NOTE:
The voltage reading should be below 4.3 V.
4. Fully lower combine feeder house until adapter is no
longer supporting header. The float indicator should
read 4.
NOTE:
You may need to hold HEADER DOWN switch for a few
seconds to ensure feeder house is fully lowered.
5. Measure voltage between ground and signal wires at
AHHC sensor in float indicator with a voltmeter (A). It
should be at low voltage limit for combine – 0.7 V.
6. If sensor voltage is not within low and high limits, or if
range between low and high limits is less than 3.0 V,
make adjustments according to
Limits, page 203.

Adjusting Voltage Limits

1. To adjust high voltage limit:
a. Extend guard angle fully. Header angle indicator
should be at D.
b. Position header 150–254 mm (6–10 in.) above
ground. Float indicator should be at 0.
c. Loosen sensor mounting bolts (A).
d. Slide sensor support (B) to right to increase high
voltage limit, or to left to decrease it.
e. Tighten sensor mounting bolts (A).
2. To adjust low voltage limit:
a. Fully extend center-link, (i.e., increase header/
guard angle to maximum). Header angle indicator
should be at D.
b. Fully lower header to ground. Float indicator should
be at 4.
214323
OPERATION
Adjusting Voltage
203
Figure 3.345: Float Indicator Reading 1 V
A
Figure 3.346: Float Indicator Reading 4.3 V
C
Figure 3.347: AHHC Sensor Assembly
A
D
B
A
Revision A