Hitachi DA-5000 - Service Point; Component Removal Procedures; Part Replacement and Maintenance Precautions

HITACHI DA-5000
SERVICE POINT
1.
How to remove the cover (Fig. 1)
Remove the screws () (4 pieces), and pull the cover
backward.
. How to remove the front panel (Fig. 2)
After removing the cover, remove the screws @ (4
pieces), and pull the front panel forward.
. How to remove the loading mechanism (Fig. 3)
After removing the front panel, remove the screw @) (4
pieces). Disconnect the connectors (3 positions) and
connector ® (1 position), then take off the loading me-
(3)
8.
(1)
(2)
connector @ (1 position).
PS P.W.B.
Open the tray, remove the power transformer securing
screws () (2 positions) and P.W.B. securing screws
(2 positions).
After removing the soldered parts (2 positions) of the
power cord, remove the power switch connector.
How to replace the Belt (Fig. 9)
Turn the pulley gear keeper counterclockwise with a
conventional type screwdriver, and remove the belt.
In this case, lift the tip of the pulley gear keeper a little.
While turning the pulley gear by hand, open the tray.
chanism upward.
Note:
Be sure to disconnect the connector @ of the flexible
P.W.B. as well.
Otherwise, there is a danger that the flexible P.\W.B. may
be damaged since the connector is pulled by lifting the
loading mechanism.
4. How to remove the tray mechanism (Fig. 4)
Put the tray in open status, disengage the rail from the
claw of the tray as shown in Fig. 4 and then move the
tray in the arrow @ direction.
(2) Take off the tray upward while holding the rail.
(1)
5.
(1)
(2)
(3)
6.
(1)
(2)
(3)
7.
(1)
(2)
Note:
Note that the lifter cam is disengaged from the disc sup-
port and the disc support is lowered, if the disc support is
pushed down.
If the disc support should be lowered, open the tray, and
push up the disc support from the underside. With this
procedure, the disc support will be restored to the origin-
(Stop the turning on approx. 20 mm inner side than the
full open status.)
(3) After setting the belt to the motor pulley with tweezers,
set it to the pulley gear. (Set the belt to the pulley gear,
while turning it. This is an easier method. Be careful
not to damage the belt with tweezers, etc.)
(4) Wipe off the oil getting on the belt with an applicator
damped with Freon. (While turning the pulley gear, wipe
all the four faces of the belt clean.)
(5) Turn the pulley gear keeper with a conventional type
screwdriver until it is fixed.
Note:
When turning the pulley gear keeper, lift its tip a little, and
execute turning gently. Otherwise, the pulley gear keeper
may be damaged.
If the pulley gear keeper is damaged, replace the loading
plate ass’y, or pulley gear keeper.
9. Checking the object lens (Fig. 10}
Take care not to dirty the objective lens of the lens actua-
tor. When the unit is not used for a long time, the lens
al position.
UH
Mounting the tray mechanism (Fig.4, 5)
Before mounting the tray mechanism, hook the pin of
the latch to the edge of the tray rack. (Fig. 5)
Put the tray in open status, and mount the tray mechan-
ism.
Move the rails in the arrow © direction as shown in Fig
4, and fix the tray.
How to Remove the Tray Panel (Fig. 6)
Open the tray.
Push up in the @ direction the claw of the tray in con-
tact with the stopper located at the left bottom of the
tray panel.
Push up the claw, and extract the tray panel in the ®
direction.
How to remove the P.W.B.
Types of P.W.B.
PY PW.B.: Key P.W.B.
PX P.W.B.: Main circuit P.W.B.
PS P.W.B.: Power supply P.W.B.
PY P.WB. (Fig. 7)
After removing the front panel, remove the screw @ (4
pieces), and release the claws (5 positions).
PX P.W.B. (Fig. 8)
After removing the securing screws @) (5 positions) and
®(1 position), remove the connectors (6 positions) and
sometimes becomes dirty. Clean the lens with a cotton
swab.
10. Checking the laser
11
(1)
(2)
= Be
The laser unit operates on 40 - 80 mA current. If the
laser operation current in the circuit exceeds 100 mA,
the laser may be defective. (The current can be mea-
sured at the ends of R209 (0.48 — 0.96V at the ends of
12Q).
. Precautions on repair service
Semiconductor laser (Fig. 11)
The semiconductor laser requires more attention to
electrostatic breakdown or surge current. Be very care-
ful not to touch the terminals of the semiconductor
laser and those of the flexible P.W.B. by hand or with a
tool.
The current — light intensity characteristic became
sharp abruptly after passing the threstold value as
shown in Fig. 11. The threshold current 1a fue is a little
different in each laser unit. Therefore, why setting the
laser beam amount after replacing the unit mechanism,
be sure to turn the control variable resiso r R205 fully
counterclockwise to set it off once, and fen increase
the level to the specified value.
Notes on handling the unit mechanism (Fg. 12)
When handling the pick-up mechanism Oru nit mechan-
ism, use the ground ring as shown in Fig. 12.
(The ground ring can be made using norm: lead wire.)