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B Hi-Fi Component




SERVICE MANUAL
MODEL DCD-485/685
STEREO CD PLAYER




DCD-485




DCD-685




Some illustration using in this service manual is slightly from the actual set.
SAFETY PRECAUTIONS


SAFETY PRECAUTIONS
The following check should be performed for the continued prtection of the customer and service
technician.
LEAKAGE CURRENT CHECK
Before reterning the unit to the customer,make sure you make either (1) a
leakage current check or (2) a line to chassis resistance check. If the leakage current exceeds 0.5
miliamps, or if hte resistance from chassis to either side of the power cord is less than 460 kohms,
the unit is detective.


SPECIFICATIONS



SPECIFICATIONS
DCD-485 DCD-685
AUDIO
Number of Channels: 2 channels
Freqency Responese: 2 to 20 kHz
Dynamic Range: 98 dB 100 dB
Signal to Noise ratio: 105 dB 110 dB
Harmonic distortion: 0.003 % (1 kHz)
Separation: 102 dB (1 kHz) 103 dB (1 kHz)
Wow and Flutter: Below measurable limit:
( 0.001 % W. peak)
Output Voltage: 0.2 to 2.0 V
DISCS Compact Disc format
GENERAL CHARACTERISTICS
Power Supply: AC 230 V, 50 Hz
Power consumption: 11 W 12 W
Dimensions: 434 (W) x 100 (H) x 285 (D) mm
Mass: 3.4 kg 3.6 kg
FUNCTIONS AND DISPLAY
Functions: Automatic searchi, programmed playback, repeat playback, manual search, auto space,
time mode, auto edit, dimmer, random playback, pitch control (DCD-685 only)
Display: Track number, time, music calendar and engaged modes
Others: Headphones jack
REMOTE CONTROL UNIT RC-266
Remote Control System: Infrared pulse system
Power Supply: 3V DC; two R6P (standard size AA) dry cell batteries
External Dimensions: 54.5 (W) x 140 (H) x 24.8 (D) mm
Mass: 85 g including batteries


Specifications and design are subject to change without notice for purpose of improvement.




2
DISASSENBLY
Follow the procedure below in reverse order when reassembling
(Follow the procedure below in reverse order when reassembling)

1. Top Cover
1. Remove 4 screws 1 on both sides.
2. Remove 2 screws 2 on the Rear Panel.
3. Detach the Top Cover as shown in the fig.




2. Front Panel
1. Remove 1 screw 3 on the Rear Panel and
1 screw 4 fixing Support Bracket (b).
(only DCD-485)
2. Take off the Mecha Cover after removing Support Bracket
2 screws 5 .
Open the Tray by turning the Gear (a) clockwise,
then detach the Loader Panel.
3. Remove 3 screws 6 on the bottom edge of the
Front Panel.
4. Remove 2 screws 7 , at L/R ends of the Front
Panel and 1 screw 8 fixing Phone P.W.B.




3
3. CD Mecha. Unit
1. Remove 4 screws 9 fixing the CD Mecha.
2. Unplug Connectors (b), (c) and FFC from each
socket.
3. Release the FFC from the Clamper.




4. Main P.W.B.
1. Remove 5 screws 10 , 5 screws 11 on the Rear
Panel and detach it.
2. Remove 3 screws 12 fixing the Main P.W.B.
3. Unfasten 1 P.W.B. Holder to detach the Main
P.W.B.
4. Remove 1 screw and 2 screw fixing the
Power P.W.B.
5. Unfasten 1 P.W.B. Holder to detach the Power
P.W.B.




4
CD TEST MODE

Setting of the test mode
How to start the test mode: Turn on the power in the condition that CLOSE (Pin No. 3 )
and OPEN (Pin No. 4 ) of CX053 are being shorted. ( "01" is indicated on the DISPLAY)
To exit from the test mode, turn off the power. (Refer to Fig. 1 "Test Point Layout")




Fig. 1 "Test Point" Layout
* Laser light of the pickup is always emitted regardless of DISC loading in the test mode.
You may lose your eyesight if you look into the laser directly.
So be careful enough when operating in the test mode.


Used DISC: A-BEX TCD784


Explanation of each button
* Use only the buttons described below for operations while in the test mode,
and don't push any other buttons.
Names of buttons Operation
OPEN / CLOSE * Loads or unloads DISC
PLAY * Emits laser light
* Repeats search operation (No DISC condition: While it's
pressed)
* Actuates focus servo (In case of DISC loaded)
* Actuates tracking servo
STOP * Stops operation
PAUSE * Performs auto adjustment
MANUAL SEARCH * Moves pickup
FORWARD / REVERSE




5
How to check the test mode
( 1 ) DISC discrimination, adjustment
* Insert DISC, and press the PAUSE button.
* "06 Adj" is displayed, and discrimination of DISC size 8 cm/12 cm, discrimination of
DISC reflectance (CD, CD-R/CD-RW), adjustment of focus, tracking offset,
and EF balance will be performed. (Adjusted values are not displayed: Refer to Fig. 2, 3)


FEO
TEO
TEO

HF TB

DRF
SLD




Fig. 2 DISC discrimination, adjustment Fig. 3
(Case of CD-RW) Adjustment of EF balance
* After completing the discrimination and adjustment, it becomes stop condition.
* Once discrimination of DISC has been carried out in the "06 Adj" mode, discrimination of
size and reflectance is no longer made, and only adjustment will be performed.


( 2 ) Checking of servo state
* Press the PLAY button after performing above (1) "DISC discrimination, adjustment".
* "02 L on" is displayed, and the laser will start to light. (The pickup may vibrate with a rattling
noise if DISC has been loaded, but this is not abnormal.)
* Press the PLAY button again.
* "03 F on"is displayed. DISC starts turning,and focus servo will be actuated. (Refer to Fig. 4, 5)



FEO TEO




TEO HF




6
Fig. 4 In "03 F on" Fig. 5 In "03 F on"
* Press the PLAY button again.
* "04 t on" is displayed. Tracking, CLV, and slide servo will be actuated.
* Monitor HF signal using the test terminals, HF of CX053 (Pin No. 1 ) and
VC of CX063 (Pin No. 5 : 2.5V ref. signal). Check that the signal's amplitude
is 1.5V 0.3Vp-p. (Refer to Fig. 6)




HF
A ( A = 1.5