Technics SJHD-501 Service manual

ORDER No.AD9907180C2

Mini Disc Deck

SJ-HD501

Mechanism unit: MR3A (RAJ3402) Mechanism Series

Colour

(N)...................Gold Type

Areas

EG...................Europe.

EB...................Great Britain.

This product is option for systems of SC-HD301 and

SC-HD501.

SPECIFICATIONS

1

Specifications

•System
Recording

Reading

Sampling
frequency:

Cording system:
Channel:
Frequency

response:
S/N Ratio (PLAY):
Wow and flutter:

•Input

Analog input
(Level/impedance):

Digital input
(Optical in 1,
Optical in 2)
Wavelength:

Minidisc digital audio system
Magnetic field modulation

direct overwrite
Non-contact optical system
with Semiconductor laser
(=780nm)

44.1 kHz

ATRAC
2channel, stereo
10-20000Hz (±0.3dB)

90dB
Below measurable limit

500mV/47k

660nm

ΩΩΩΩ

•Output

Analog output
(Level/impedance):

•General

Dimensions
(WxHxD):

Weight:
Power supply:
Power

consumption:

Notes:

1.Design and specifications are subject to
change without notice.

2.Dimensions and weight are approximate.

3.Total harmonic distortion is measured by the
digital spectrum analyzer.

2.0V/600

196x104x237mm

2.0kg
AC230-240V, 50Hz
12W

ΩΩΩΩ

1

2

1. Accessories

-

AC power supply cord...............1pc.

-

Optical cable...............1pc.

(RJL1X001B05D)

3

-

Remote control batteries...............2pcs.

[R6/LR6 (AA, UM-3) ]
Note:These are available on sales route.

-

Stereo phono cables...............2pcs.

(RJL2P004B08)

-

Remote control transmitter...............1pc.

(EUR645272)

4

2. Precation of Laser Diode

5

3. Caution for AC Main Lead

4. Operating Instructions

5. Handling Precautions for Traverse Deck (MD Unit)

The laser diode in the MD unit (optical pickup) may break down due to potential
difference caused by static electricity of clothes or human body.So, be careful of

6

electrostatic breakdown during repair of the MD unit (optical pickup).

5.1. Handling of MD Unit (optical pickup)

1. Do not subject the MD unit (optical pickup) to static electricity as it is extremely
sensitive to electrical shock.

2. The short land between the No. 25 (LD-GND) and No. 24 (LD) pins on the flexible
board is shorted with a solder build-up to prevent damage to the laser diode. (As
shown in
To connect to the PC board, be sure to open by removing the solder build-up, and
finish the work quickly.

3. Take care not to apply excessive stress to the flexible board (FFC).

4. Do not turn the variable resistor (laser power adjustment). It has already been
adjusted.

Fig. 1.)

Fig. 1

7

5.2. Grounding for electrostatic breakdown prevention

1. Human body grounding
Use the anti-static wrist strap to discharge the static electricity from your body.
(As shown in

2. Work table grounding
Put a conductive material (sheet) or steel sheet on the area where the optical
pickup is placed, and ground the sheet.

Caution:

The static electricity of your clothes will not be grounded through the wrist strap.
So, take care not to let your clothes touch the traverse deck (optical pickup).

Fig. 2.)

Fig. 2

6. Operation Checks and Main Component Replacement

8

Procedures

910111213

14

7. Self-Diagnostic Function

This unit is equipped with a self-diagnostic function which, in the event of a
malfunction, automatically display a code indicating the nature of the malfunction.
Use this self-diagnostic function when servicing the unit.

7.1. Switching to the Self-Diagnostic Mode

1. Turn the power on.

2. Press and hold the STOP button for at least 2 seconds, and while still pressing the
STOP button, press the FWD SEARCH button for at least 2 seconds. (Refer to

Fig.1.) The unit enters Self-Diagnostic Mode and is displayed “MD TEST”. Then an

error code is displayed, if any. For details of the error codes, refer to

Fig.2. In the

case of no errors, “

3. If more than one error exists, the display will sequentially show the respective
error codes each time the FWD SEARCH button is pressed.

----” is displayed on FL.

7.2. Canceling the Self-Diagnostic Mode

1. The Self-Diagnostic Mode can be canceled by pressing the POWER button
(POWER) to turn the system off. And then pressing the power button again to turn
it again.

7.3. Clearing the Self-Diagnostic Mode

1. The contents of abnormality display are stored in memory. In order to clear the
memory, continue to press the STOP button for at least 5 seconds while in the
Self-Diagnostic Mode. The memory will clear. Always be sure to clear this memory
after completing repair.

Fig.1

15

Fig.2

16

8. Self Check Function

This unit is equipped with a self check function which can detect a part of
malfunction. Use this function before servicing the unit and check the item as shown
below.

8.1. Setting to the Self Check Function

1. Turn the power on.

2. Press and hold the STOP button for at least 2 seconds, and while still pressing the
STOP button, press the REV. SEARCH button for at least 2 seconds. Then the unit
enters Self Check Function. (Refer to

Fig.3.)

Fig.3

8.2. Checking the operation switches

1. When the unit enters the Self Check Function, the FL display turn off.

2. Press the buttons on the unit except the INPUT SELECTOR button, it displays “-”
mark adapted each buttons.
(

Fig.4 and Fig.5 is shown about a allotment.)

17

Fig.4

Fig.5

8.3. Checking the FL display

1. Press the INPUT SELECTOR button.

2. All buttons works normally except the POWER button, FL display and LED turns on
and off at 0.5 second interval.
(Refer to

Fig.6 and Fig.7.)

Fig.6

18

Fig.7

The Self Check Function can be canceled by pressing and holding the STOP
button for at least 2 seconds.

9. Measurements and Adjustments (Laser Power

Adjustment)

Note:

-

If you exchange parts of MD unit when you repair, you must perform the Laser

Power adjustment.

19

-

Because this unit uses the optical magnetic recording, the unit outputs over 10

times more laser than a CD player does. In the adjustment mode, the laser is
always being output. Therefore, be especially careful not to look laser beam
directly or to touch the laser beam when adjusting the unit and checking its
operation.

9.1. Necessary Instruments

-

Laser power meter (LE8010) or cartridge type laser power meter

-

Test disc (Pre-mastered disc RFKV0006 or RFKV0014)

-

Recordable disc available on sales route (with music recorded)

-

Insulated driver for adjustment such as a ceramic driver

-

Remote control transmitter

9.2. Set the Unit to the Adjustmint Mode

1. Supply power to the unit.

2. With no MD loaded in the player, simultaneously press the [

[
seconds until “MD TEST” appears in the display. (Refer to

3. At the Self-Diagnostic Mode, press “1” on the player’s remote control. “RAM
LASER” will be displayed to indicate the read power adjustment mode.

FWD. SEARCH] button and hold them both pressed for at least 2

Fig.8

STOP] button and the

Fig.8.)

20