MacDon FD75 OM - Manual (Page 73)

OPERATION
Manually Checking Voltage Range
You can manually check the output voltage range of the auto header height sensor at the float indicator box. Some
combines will allow you to check the voltage range from the cab. For instructions, refer to your combine operator’s
manual or the auto header height instructions for your combine model later in this document.
To manually check the sensor’s output voltage range,
follow these steps:
1. Position the header 6 in. (150 mm) above the ground.
Unlock the adapter float.
NOTE:
If the header is not on down stops during the
next two steps, the voltage may go out of range
during operation, causing a malfunction of the
Auto Header Height system.
2. The pointer (A) on the float indicator box should point
at zero. If it does not point at zero, adjust the cable
take-up bracket (B) until it does.
Figure 4.35: Float Indicator Box
3. 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 high
voltage limit for the combine, Refer to
Height Sensor
Output Voltage Range – Combine Requirements, page
58
.
Figure 4.36: Measuring Voltage Between
Ground and Signal Wires with a Voltmeter
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