Read Harman Kardon HD 755 (serv.man9) Service Manual online
Technical Manual
The Harman Kardon
Model HD755 silver
Model HD755 silver
COMPACT DISC PLAYER
DANGER: Invisible laser radiation when open and interlock failed or defeated.
AVOID DIRECT EXPOSURE TO BEAM.
CONTENTS
Parts and Service Office
250 Crossways Park Dr., Woodbury, N.Y. 11797
1112-FL8350 P9603 1200 Printed in Hong Kong
1. LASER BEAM SAFETY PRECAUTIONS ............. 2
2. CONTROL AND FUNCTIONS ............................. 4
3. SPECIFICATIONS AND FEATURES ..................... 7
4. AUDIO CHARACTERISTICS TEST PROCEDURE
2. CONTROL AND FUNCTIONS ............................. 4
3. SPECIFICATIONS AND FEATURES ..................... 7
4. AUDIO CHARACTERISTICS TEST PROCEDURE
.............................................................................. 9
5. CIRCUIT DESCRIPTION ....................................11
6. CRITICAL I.C. SPECIFICATION ........................ 15
7. PART LIST ......................................................... 41
6. CRITICAL I.C. SPECIFICATION ........................ 15
7. PART LIST ......................................................... 41
9. BLOCK DIAGRAM ............................................. 54
10. SCHEMATIC DIAGRAMS .................................. 55
11. PCB LAYOUT ..................................................... 59
12. EXPLODED VIEW .............................................. 62
13. PACKING DRAWING ......................................... 63
10. SCHEMATIC DIAGRAMS .................................. 55
11. PCB LAYOUT ..................................................... 59
12. EXPLODED VIEW .............................................. 62
13. PACKING DRAWING ......................................... 63
* Harman/ kardon continually strives to improve its products. The HD750 Compact Disc Player design and
specifications are subject to change and may differ from the published specifications and descriptions, but will
always equal or exceed the original specifications unless otherwise stated.
8. TROUBLE SHOOTING GUIDE .......................... 48
Standby
HD755
LASER BEAM SAFETY PRECAUTIONS
CLASS 1 LASER PRODUCT
CAUTION
Invisible laser radiation when the unit is open.
Do not stare into beam.
Invisible laser radiation when the unit is open.
Do not stare into beam.
CAUTION: USE OF ANY CONTROLS, ADJUSTMENT, OR
PROCEDURES OTHER THAN THOSE SPECIFIED HEREIN
MAY RESULT IN HAZARDOUS RADIATION EXPOSURE.
PROCEDURES OTHER THAN THOSE SPECIFIED HEREIN
MAY RESULT IN HAZARDOUS RADIATION EXPOSURE.
Do not look directly at the laser beam
coming from the pickup or allow it to
strike against your skin.
coming from the pickup or allow it to
strike against your skin.
This compact disc player uses a pickup that emits a laser beam. The laser beam is emitted from the
location shown in the figure. When checking the laser diode, be sure to keep your eyes at least 1 foot away
from the pickup lens when the diode is turned on. Do not look directly at the laser beam.
location shown in the figure. When checking the laser diode, be sure to keep your eyes at least 1 foot away
from the pickup lens when the diode is turned on. Do not look directly at the laser beam.
CAUTION:
Using controls and adjustment, or doing procedures other than those specified herein, may result in
hazardous radiation exposure.
hazardous radiation exposure.
2
HD755
SAFETY PRECAUTIONS
This symbol is intended to alert the user to
the presence of uninsulated "dangerous
voltage" within the product's enclosure that
may be of sufficient magnitude to consti-
tute a risk of electric shock to persons.
the presence of uninsulated "dangerous
voltage" within the product's enclosure that
may be of sufficient magnitude to consti-
tute a risk of electric shock to persons.
This symbol is intended to alert the user to
the presence of important operating and
maintenance (servicing) instructions in the
literature accompanying the appliance.
the presence of important operating and
maintenance (servicing) instructions in the
literature accompanying the appliance.
Caution:
To prevent electric shock do not use this
(polarized) plug with an extension cord, recep-
tacle or other outlet unless the blades can be
fully inserted to prevent blade exposure.
(polarized) plug with an extension cord, recep-
tacle or other outlet unless the blades can be
fully inserted to prevent blade exposure.
Attention: Pour prevenir les chocs electriques ne pas
utiliser cetre fiche polarisee avec un
prolongateur, une prise de courant ou une au-
tre sortie de courant, sauf si les lames prevent
etre inserees a fond-sans en laisser aucune
partie a decouvert.
prolongateur, une prise de courant ou une au-
tre sortie de courant, sauf si les lames prevent
etre inserees a fond-sans en laisser aucune
partie a decouvert.
HANDLING LASER PICKUP
The laser diode in the optical system of this player can be damaged by electrostatic discharge from
your clothes or your body. Proper electrostatic grounding for service personal is required during servicing.
your clothes or your body. Proper electrostatic grounding for service personal is required during servicing.
BEFORE REPAIRING THE COMPACT DISC PLAYER
Preparation
Human Body Grounding:
Many of the components used in this compact disc player, including the laser pickup, are sensitive to
electrostatic discharge. Service personal should be grounded with an electrostatic armband (1 Mohm).
Human Body Grounding:
Many of the components used in this compact disc player, including the laser pickup, are sensitive to
electrostatic discharge. Service personal should be grounded with an electrostatic armband (1 Mohm).
Caution:
Static charge on clothing does not escape through a body grounding wrist band.
Be careful not to contact the pickup or electrical components with your clothing.
Static charge on clothing does not escape through a body grounding wrist band.
Be careful not to contact the pickup or electrical components with your clothing.
Workbench and Tool Grounding:
A properly-grounded electroconductive plate (1Mohm) or metal sheet should be fitted to the workbench
surface. Tools and instruments (such as soldering irons and scopes) should be grounded to prevent AC
leakage.
A properly-grounded electroconductive plate (1Mohm) or metal sheet should be fitted to the workbench
surface. Tools and instruments (such as soldering irons and scopes) should be grounded to prevent AC
leakage.
Note: Laser diodes are so susceptible to damage from static electricity that, even if a static discharge does
not ruin a diode, it can shorten its life or cause it to work improperly.
not ruin a diode, it can shorten its life or cause it to work improperly.
WARNING
To prevent fire or shock hazard, do not
expose the unit to rain or moisture.
expose the unit to rain or moisture.
3
HD755
HD755
Power: Press this switch to apply power to
the HD750. Then the Status-Mode Indicator
1 will turn green, the Information Display
the HD750. Then the Status-Mode Indicator
1 will turn green, the Information Display
C will illuminate and all trays will be checked
automatically for discs. Press the switch again to
turn the unit off; the Status-Mode Indicator
1 will turn amber, indicating that the unit is in
Standby. When the HD750 is connected to a
switched AC outlet, such as those found on the
back of many audio products, and the AC outlet
will be turned on, the unit will turn to Standby
mode only.
automatically for discs. Press the switch again to
turn the unit off; the Status-Mode Indicator
1 will turn amber, indicating that the unit is in
Standby. When the HD750 is connected to a
switched AC outlet, such as those found on the
back of many audio products, and the AC outlet
will be turned on, the unit will turn to Standby
mode only.
1 Status-Mode Indicator: When the
HD750 is in the On mode, this indicator will
glow green. When the unit is off, the indicator
will glow amber, indicating that the unit is still
connected to AC power.
HD750 is in the On mode, this indicator will
glow green. When the unit is off, the indicator
will glow amber, indicating that the unit is still
connected to AC power.
2 Headphones Jack: Connect a set of stan-
dard headphones to this jack for private listening.
dard headphones to this jack for private listening.
3 Headphones Level Control: Turn this knob
to increase or decrease the volume level for
headphones connected to the HD750’s
Headphones Jack
to increase or decrease the volume level for
headphones connected to the HD750’s
Headphones Jack
2. Note that changing this
level will not change the sound level for the
unit’s main output, as that remains constant.
unit’s main output, as that remains constant.
4 CD Drawer: This drawer holds the discs
that will be played. Press the Open/Close but-
ton
that will be played. Press the Open/Close but-
ton
5 to open the drawer so that discs may be
inserted.
5 Open/Close: Press this button to open or
close the disc drawer. DO NOT push the drawer
to close it or damage to the transport mecha-
nism may result.
close the disc drawer. DO NOT push the drawer
to close it or damage to the transport mecha-
nism may result.
6 Search: Press one side of this button to
search forward — or the other side of the
button to search backwards ‚ through a
disc to locate a particular portion of the disc
being played.
search forward — or the other side of the
button to search backwards ‚ through a
disc to locate a particular portion of the disc
being played.
7 Skip: Press the right side of this button to
move to the next track fl· or the left side of
the button to move back to the previous track
‡fi
move to the next track fl· or the left side of
the button to move back to the previous track
‡fi
on the disc being played.
8 Stop: Press this button to stop the disc cur-
rently being played. During programming
functions, this button is also used to exit the pro-
rently being played. During programming
functions, this button is also used to exit the pro-
9 Play/Pause Button: Press this button to
start the playback of a CD. If the CD drawer is
open, pressing this button will automatically
close the drawer. When a disc is playing press
this button once to momentarily stop a disc.
When the button is pressed again, the disc will
resume play at the point it was stopped.
start the playback of a CD. If the CD drawer is
open, pressing this button will automatically
close the drawer. When a disc is playing press
this button once to momentarily stop a disc.
When the button is pressed again, the disc will
resume play at the point it was stopped.
A Intro Button: Press this button to put the HD750
in teh Intro Scan mode. When you press the button, the
unit will play the first 10 sec of each track on the disc, and
then move to the next track. Press the button again to
defeat the function and continue full play of the current track.
in teh Intro Scan mode. When you press the button, the
unit will play the first 10 sec of each track on the disc, and
then move to the next track. Press the button again to
defeat the function and continue full play of the current track.
B HDCD Indictaor: The LED will light automatically
when a CD with HDCD encoding is playing. No
further action is needed to enjoy the benefits of HDCD.
when a CD with HDCD encoding is playing. No
further action is needed to enjoy the benefits of HDCD.
C Information Display: This display
provides details about the operation of the
HD750.
provides details about the operation of the
HD750.
D Remote Sensor: The sensor behind this
window receives commands from the remote
control. Keep this area clear if you wish to use
the HD750 with a remote control.
window receives commands from the remote
control. Keep this area clear if you wish to use
the HD750 with a remote control.
Front Panel Controls
1
2
3
4
5
6
7
8
9
A
B
C
D
Power Switch
Status Mode Indicator
Headphones Jack
Headphones Level Control
CD Drawer
Status Mode Indicator
Headphones Jack
Headphones Level Control
CD Drawer
Open/Close Button
Search Button
Skip Button
Stop Button
Play/Pause Button
Search Button
Skip Button
Stop Button
Play/Pause Button
Repeat Button
HDCD Indicator
Information Display
Remote Sensor
HDCD Indicator
Information Display
Remote Sensor
Important Note: When the unit is turned off
(to Standby), pressing any button on the front
panel will turn the unit on. When Play 5 10
on the front or on the remote is pressed, the unit
will automatically turn on and start playing the disc
on the front or on the remote is pressed, the unit
will automatically turn on and start playing the disc
actually loaded.
gram mode.
Program Button: This button is used to
program the playback of a disc in a particular
order.
Repeat Button: Press this button once to
repeat only the tracfk currently being played. Press
it again to continually repeat all tracks on a disc.
Random Button: Press this button to
have all of the tracks played in a random order.
Program Button: This button is used to
program the playback of a disc in a particular
order.
4
Standby
1 2
6
3 4
8
7
15
16
17
9
10
13
14
12
11
5
15
16
17
15
16
17
Program Button
Random Button
Repeat Button
