Hitachi H90SE Instruction Manual - Page 13

English MAINTENANCE AND INSPECTION WARNING: Be sure to switch power OFF and disconnect the plug from the receptacle during maintenance and inspection. 1. Inspecting this demolition hammer Since use of a dull accessory, such as a bull point, a cutter, etc., will degrade efficiency and cause possible motor malfunction, sharpen or replace with a new one as soon as 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 loosened, retighten them immediately. WARNING: Using this demolition hammer with loosen screws is extremely dangerous. 3. Inspecting the retainner (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. 8) The Motor employs carbon brushes which are consumable parts. When they become No. of carbon Wear limit brush worn to or near the "wear limit", it results in motor trouble. When an auto-stop carbon brush is equipped, the motor will stop 86 automatically. At that time, replace both 0.28" (7 mm) carbon brushes with new ones which have the same carbon brush Numbers shown in the figure 8. In addition, always keep carbon 0.67" (17 mm) brushes clean and ensure that they slide freely within the brush holders. Fig. 8 NOTE: Use HITACHI carbon brush No. 86 indicated in Fig. 8. 5. Replacing carbon brushes (Refer to figure for name of parts) Loosen the screws (Hexagon socket hd. bolt M4 × 10) of the cap covers, then remove the cap covers. After removing the brush caps, the carbon brushes can be removed. After replacing the carbon brushes, tighten the brush caps, then mount the cap covers securely. 6. Grease replacement This demolition hammer is of fully oil sealed construction to protect against dust incursion and to prevent lubricant leakage. This demolition hammer can be used without grease replenishment for an extended period of time. However, perform the grease replacement to extend the service life. Replace the grease as described below. 13