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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 screws

Regularly inspect all 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. 20)

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.

Wear limit

No. of carbon brush

73

0.28" (7 mm)

0.67" (17 mm)

Fig. 20

NOTE:

Use HITACHI carbon brush No.73 indicated in Fig. 20

￿Replacing carbon brushes: (For parts name, refer to Fig. 1)

Loosen the two set screws and remove the tail cover. Remove the brush caps and carbon brushes. After replacing the carbon brushes, tighten the brush caps securely and to install the tail cover with securely tightening two set screws.

5.How to replase grease

This machine is full air-tight construction to protect against dust and to prevent lubricant leakage. Therefore, the machine can be used without lubrication for long periods. Replace the grease as described below.

￿Grease replacement period

After purchase, replace grease after every 6 months of usage. Ask for grease replacement at the nearest HITACHI Authorized Service Center. Proceed for replacement of grease.

￿Grease replenishment

CAUTION:

Before replenishing the grease, turn the power off and pull out the power plug.

(1)Remove the crank cover and wipe off the grease inside.

(2)Apply 1.0 oz (30 g) of HITACHI Electric Hammer Grease A (standard accessory, contained in tube) to the crank case.

(3)After replenishing the grease, install the crank cover securely.

Crank cover

Fig. 21

NOTE:

The HITACHI Electric Hammer Grease A is of the lower viscosity type. When the supplied grease tube is consumed, purchase from a HITACHI Autorized Service Center.

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