John Deere Combines 6620, Side Hill 6620, 7720, 8820. Hydraulic Operations and Tests - part 8

DIAL-A-MATIC HEADER HEIGHT CONTROL

Construct a special tester from repair kit. This will allow continuity testing of a harness without using a long length of wire and making six trips to the other end of the harness

1. Insert contacts of special tester into contacts of firewall connector. Clamp alligator clip to combine frame.

2. Test continuity of wires at feeder house connector.

1. Insert contacts of special tester into contacts of firewall CPC connector. Clamp alligator clip to combine frame

2. Be certain feeder house is lowered.

3. Test continuity of pins 1. 3. and 9 in amplifier CPC connector.

1. Construct special tester as shown in step 59.

2. Disconnect feeder house connector.

3. Insert contacts of special tester into contacts of header harness.

4. Disconnect connector at sensing box. Test continuity of wires.

Connectors on auto header valve may be switched. Orange wire must go to outside or loft hand solenoid.

Contacts are placed wrong in the connectors or a flex platform harness was installed on a row-crop head or a row-crop head harness on a flex platform.

If this problem only occurs in the medium ground pressure position then check firewall CPC connector. The header harness must have four wires misplaced for this symptom. The combine harness must have circuits 63 and 65 crossed orcircuits67 and 68 crossed.

Group 30 DIAL-A-MATIC HEADER HEIGHT CONTROL MECHANICAL SYSTEM ROW-CROP HEAD

GENERAL INFORMATION

The Dial-A-Matic header height control maintains the correct position of the header frame by sensing the position of each individual row unit. Individual row units are designed to pivot independently about the common drive shaft and have a (152 mm) 6 inch float range measured at skid shoe.

IMPORTANT: For the Dial-A-Matic header height control to perform correctly, row units must be in floating position and correct row unit float spring tension and gatherer sheet clearance must be maintained. Row unit skid shoes must be adjusted for correct cutting height.

The Dial-A-Matic header height control works as follows:

1. When one or more row units deflect up to follow ground contour, height sensing shaft (A) (Fig. 1) turns linkage assembly (B) which in turn moves wiper arm (C) in sensing box (D),

2. Movement of wiper arm (C) contacts one of five printed circuit pads in the sensing box.

3. The pad that is contacted activates the system for raising or lowering the row-crop head.

4. When the wiper arm contacts the “raise" pad. the row-crop head raises.

5. When the wiper arm contacts the 'lower" pad, the row-crop head lowers,

6. If additional movement is required loosen the lock nut and remove ball joint from arm. Shorten the rod for raising and lengthen the rod for lowering. Replace ball joint in arm and tighten lock nut.

7. The sensing box sends low current signals to the amplifier. The amplifier amplifies this current into high powered signals to the solenoids on the auto header valve.

8. The auto header valve, directs hydraulic oil under pressure to the two header lift cylinders to raise and allows return oil to flow back to hydraulic reservoir for lowering header.

9. The actuating switch, located under operator's station shuts off the Dial-A-Matic header height control when header is raised approximately 18 inches (457 mm) above ground.

Switch Positioning for Ground Conditions

Dry ground conditions allow a heavier ground force fora close cut. The header must be operated with the rotary switch in 1st position. Solt ground conditions require the rotary switch to be in 2nd position. Wet ground conditions require the rotary switch to be in 3rd position. Additional adjustment is made by loosening lock nut on a ball joint and removing ball joint from arm. Shorten rod to raise or lengthen rod to lower. Replace ball joint in arm and tighten lock nut.

A float spring supports each row unit. As the row unit is raised, spring tension is relieved causing skid shoe ground force to increase. The actual value of pounds of ground force is dependent on the float spring tension adjustment. However, the ground force will increase by approximately (50.8 kg) 90 lbs when the row unit is raised from the lower mechanical stop to the upper mechanical stop. Be certain to:

1. Check adjustment of inner gatherer sheet clearance,

2, Turn drop rale valve adjusting screw out until header "hunts'- or cycles up and down. Turn adjusting screw in until header stops "hunting" then turn adjusting screw in an additional 1/2 turn.

200 SERIES PLATFORM

GENERAL INFORMATION

The flexible cutterbar Moats within a (102 mm) 4-inch range. When any one section of the cutterbar floats higher than the rest, stop arm (A) (Fig. 2) moves actuator arm (B) and causes height sensing tod (C) to turn. Actuator arm rests on top of the stop arm preventing turning of the heght sensing rod, if one section of the cutterbar floats down lower than other sections. This makes the highest section of cutterbar control the Dial-A-Matic header height control system

The curved transition sheet between the cutterbar and the platform bottom operates as a leaf spring supporting weight of the cutterbar. As the cutterbar is raised within its float range, tension is relieved from the transition plate, causing the cutterbar to become heavier and causing a higher ground force.

Switch Positioning for Ground Conditions

Dry ground conditions require a heavier ground force while soft or wet ground conditions require less ground force. The first switch position (Fig, 3) provides highest ground force and second and third positions provide progressively less force. There is a fixed area of (25 mm) 1-inch between the raise and lower signals in all three positions.

Use the first position whenever possible since this position gives the closest cut and best feeding (transition sheet is flattest and cutterbar is closer to reel in this position). If the platform pushes dirt or material at the center or right-hand end move switch to second or third position. If pushing occurs at left-hand end adjust cutterbar drive case spring

Adjusting Sensing Box on Platform

In extremely dry conditions the platform may climb up and over soybean stubble. If this occurs, loosen adjusting nut (A) (Fig. 4) and rotate housing toward (B).

This will move the three ranges closer to upper stop and increase ground pressure. After making this adjustment always field test or lower left-hand end of cutterbar on a 4 x 4 to see that a raise signal can be obtained with switch in 1st position. If raise signal cannot be obtained in 1st position, loosen nut (A) and rotate housing toward (C).

Range Indicator

Group 35 DIAL-A-MATIC HEADER HEIGHT CONTROL ELECTRICAL SYSTEM
GENERAL INFORMATION
The electrical portion of the Dial-A-Matic header height control consists of these components. Refer to the wiring diagram at the end of this group to see how they are linked electrically.

The control switch for the header height control is mounted on the instrument panel (Fig. 2). This switch can turn off the system or set it to one of three

positions.

IMPORTANT: Turn oft the system when transporting the combine.

When the control switch is opened bv the operator, the entire header height control system is turned off.

Group 40 DIAL-A-MATIC HEADER HEIGHT CONTROL HYDRAULIC SYSTEM

MAIN CONTROL VALVE

SECONDARY CONTROL VALVE

GENERAL INFORMATION

The Dial-A-Matic header height control hydraulic Height Control Activated system and unloading auger swing hydraulic system use the oil coming Irom the flow control plug in the main control valve

Height Control Not Activated

AUTO HEADER VALVE
GENERAL INFORMATION

The auto header valve Is located next to the operator's platform ladder The auto header valve directs pressure oil to the header lift cylinders and directs return oil to the reservoir.

The leveling control valve for the SideHill leveling system and ihe auto header valve for the DIal-A-MatIc header height control are similar in appearance, but they have these differences.

1. Only the SideHill leveling control valve has thermal relief valves.
2, The check block on the SideHill leveling control valve may be Installed in either direction on the valve. The check block on the auto header valve must be installed in only one position. Mark check block to auto header valve before removal.

3. The auto header valve contains an internal orifice or leak off passage, the SideHill valve does not. Remove the raise solenoid to see this orifice.

GENERAL INFORMATION—Continuod

DROP RATE VALVE—CONTINUED

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