Komatsu PC78US-6 Operation & Maintenance Manual page 70

DETAILED CONTROLS AND GAUGES
NOTICE
This switch is installed to make it possible to carry out operation temporarily if any abnormality should occur in the pump
control system. It is not intended for permanent use. Repair the cause of the abnormality immediately.
If this switch is depressed and moved to the EMERGENCY position by mistake, thereby engaging the machine in the work,
while the machine is in normal condition, an "E02" mark is shown in the display.
If "E02" is displayed during the work, check that the switch is in the NORMAL position.
NOTICE
This switch is installed to make it possible to carry out operation temporarily if any abnormality should occur in the swing brake
system. It is not intended for permanent use. Repair the cause of the abnormality immediately.
If this switch is depressed and moved to the EMERGENCY position by mistake, thereby engaging the machine in the work,
while the machine is in normal condition, an "E03" mark is shown in the display.
If "E03" is displayed during the work, check that the switch is in the NORMAL position.
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OPERATION