Hitachi D 550 U Service Manual

Page 2

0-550 (U) I

SAFETY PRECAUTION

The following precautions should be observed when servicing.

1. Since many parts in the unit have special safetyrelated characteristics.
always use genuine Hitachi's replacement parts. Especially critical parts
in the power circuit block should not be replaced with other makers,
Critical parts are marked with t in the schematic diagram, and circuit
board diagram.

2. Before returning a repaired unit to the customer. the service technician
must thoroughly test the unit to ascertain that it is completely safe to
operate without danger of electrical shock.

EXPLANATION OF NEW DECK CHASSIS

1. Power-assisted oontml mechanism
1) When the playback button is pressed. the playback slider
shown in Fig.1 slides in the direction of the arrow 6)
After this. the gear-drive arm and the playback lock plate

0
slide in the directions of arrows ® and © and lock in kg Playback lock plate
CD

the positions shown in color, by means of the playback lock

plate. V - "l , . 00 l
At the same time. the motor switch turns ON* by means i {6 - Q
of the movement of the lock plate, the motor starts and the _ ' k .
flywheel rotates in the direction of arrow @ (Fig. 2). fl E E Ge'apdm am
Li :Sifllfiidnim
Motor switch i Lock plate

Piayback slider

2) As the gear-drive arm slides to the position shown in color
by Item 1) as shown in Fig, 2. the shaft A. which is attached
to the playback gear moves along the inclined surface of the
gear-drive arm to make the playback gear rotate in the
direction of arrow © so that 1 or Z teeth of the gear
engage the gear of the flywheel.

The engaged gear wheel which has been engaged rotates
because of the flywheel. and continues to rotate in the
direction of arrow CS) .

3) Fig. 3 shows the connection of the shaft of the playback 9

plate and playback arm which operate the head plate and \ playback...

pressure roller. Bus d9 mu"
Following the romtion of the playback gear. the shaft B.
which is attached to the playback gear. rotates in the direc-
tion of arrow © shown in F ig, 4. whereby the playback
arm slides in the directions of arrows ® and 9 .and
the playback plate. which is connected via the shaft. slides

in the direction of arrow 63) shown in Fig 3.

Head We Playback plate
Plaque 42 late Plaque a; 1mm __ stow mode
_. Playback mime
F lg. 3