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MAINTENANCE AND INSPECTION
WARNING: Be sure to switch power OFF and disconnect the plug from the
receptacle during maintenance and inspection.
1. Inspecting the drill bits
Since use of a dull tool will cause motor malfunctioning and degraded efficiency,
replace the drill bit with a new one or resharpening without delay when abrasion
is noted.
2. Inspecting the mounting screws
Regularly inspect all mounting screws and ensure that they are properly
tightened. Should any of the screws be loose, retighten them immediately.
WARNING: Using this rotary hammer with loosen screws is extremely
dangerous.
3. Maintenance of the motor
The motor unit winding is the very “heart” of the power tool. Exercise due care
to ensure the winding does not become damaged and/or wet with oil or water.
4. Inspecting the carbon brushes: (Fig. 18)
The motor employs carbon brushes which are consumable parts. When they
become worn to or near “wear limit”, it could result in motor trouble. When an
auto-stop carbon brush is equipped, the motor will stop automatically. At that
time, replace both carbon brushes with new ones which have the same carbon
brush Nos. shown in the figure.
In addition, always keep carbon brushes clean and ensure that they slide freely
within the brush holders.
CAUTION: Using this rotary hammer with a carbon brush which is worn in
excess of the wear limit will damage the motor.
NOTE: Use HITACHI carbon brush No.73 indicated in Fig. 18
Wear limit
No. of carbon brush
0.28" (7 mm)
0.67" (17 mm)
73
Fig. 18