INTRODUCTION 777 SERVICE MANUAL
1-50 Published 10-01-2012, Control # 045-08
used to increase or decrease the displacement of each
pump to control both system working pressures.
Open Bucket
See Figure 1-33 for following procedures.
When front hoist control handle is pushed forward, the PC
closes a regulated voltage circuit to the front hoist pump
EDC. The EDC tilts the pump swashplate in the lowering
direction, causing the bucket to open with the closing line.
The PC governs the opening speed by varying the current to
the EDC in conjunction with movement of the front hoist
control handle.
NOTE: During clamshell open bucket condition, rear drum
pawl is out and rear drum brake switch is closed.
FIGURE 1-35
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