Hitachi WH 14DMR Technical Data And Service Manual page 38

(e) Mount the DC-Speed Control Switch [38] <35> to housing (A) so that the protrusion of the forward/reverse
lever at the top of the switch is inserted into the hole of Pushing Button (B) [39] <36>. Apply silicone
grease (KS609, Shin-Etsu Chemical Co., Ltd.) to the contacting surfaces of the FET of the DC-Speed
Control Switch [38] <35> and Dust Guard Fin (B) [29] <26> then mount them to housing (A).
NOTE: (1) The temperature of the FET may be high if the silicone grease is not applied. Make sure
that the three internal wires from the FET are passed above the DC-Speed Control
Switch [38] <35> (see Fig. 17).
(2) If there is no plating and a black oxide is formed on the terminal support where the
battery contacts, replace the terminal support with new one (Code No. 323710).
Otherwise, heat is generated due to contact failure and the battery or the main body may
be faulty.
(f) Apply silicone rubber (ThreeBond 1211) to housing (A) and Inner Cover (B) [25] <22> as illustrated in
Fig. 17. Attach the strap to the boss as shown in Fig. 17, then mount housing (B) and tighten the eight
Tapping Screws (W/Flange) D4 x 20 [33] <30>. Wipe off silicone rubber protruded from the housing with a
cloth.
Position the blade of dust guard
fin (B) under the rib of housing (A).
(3) Mounting the mechanical parts
(a) Mount the Hammer [12] <9> containing the twenty-eight Steel Balls D3.175 [13] <10>, Washer (J) [14]
<11> and Hammer Spring (F) [15] <12> to Spindle [18] <15>.
(b) Align the top of the cam groove on the Spindle [18] <15> with the steel ball guide groove on the Hammer
[12] <9> as illustrated in Fig. 3. Press down either of the raised faces of the Hammer [12] <9> with a hand
press to compress Hammer Spring (F) [15] <12> until the end surface of the Hammer [12] <9> contacts
the Spindle [18] <15>.
Attach the strap to the boss.
Fig. 17
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Apply silicone rubber.