Hitachi H90SB OM H 90SB Instruction Manual page 9

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. Failure to do so could
result in serious hazard.
3. Inspecting the retainer (Fig.2 and 3)
The retainer may become loose due to excessive use. Always, pay attention to its proper
functioning to securely hold the accessory shank portion. If any wear and tear is found,
bring this demolition hammer to an authorized service center for maintenance service.
4. Inspecting the carbon brushes: (Fig. 4)
The motor employs carbon brushes which are consumable parts. When they become
worn to or near "wear limit", it results 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 No. shown in the Fig. 4.
In addition, always keep carbon brushes clean and ensure that they slide freely within
the brush holders.
5. Replacing a carbon brush
Loose the screw (Hexagon socket hd. bolt M5 x 10) of the tail cover, then remove the
tail cover. (Fig. 1) After removing the brush cap, the carbon brush can be removed.
After replacing the carbon brush, tighten the brush cap, then mount the tail cover
securely.
NOTE:
Due to HITACHI's continuing program of research and development, the specifications herein
are subject to change without prior notice.
Wear limit
No. of Carbon
Brush
Fig. 4
Usual carbon brush
Auto-stop carbon
brush
No. of
carbon brush
44
74
8