Sony HCDGSX-75 Service manual
HCD-GSX75
SERVICE MANUAL
Ver. 1.3 2005.05
HCD-GSX75 is the Amplifier, CD player, Tape
Deck and Tuner section in MHC-GSX75.
CD
Section
TAPE
Section
US Model
Canadian Model
Model Name Using Similar Mechanism HCD-GS300AV
CD Mechanism Type CDM64C-K1BD47B
Base Unit Name BU-K1BD47B
Optical Pick-up Name KSM-213BFN
Model Name Using Similar Mechanism HCD-GS300AV
Tape Transport Mechanism Type CMAL1Z234A
SPECIFICATIONS
Main Unit
Amplifier section
For the U.S. model
AUDIO POWER SPECIFICATIONS
POWER OUTPUT AND TOTAL HARMONIC
DISTORTION:
With 6-ohm loads, both channels driven, from 120 – 10,000 Hz; rated 150
watts per channel minimum RMS power, with no more than 10% total
harmonic distortion from 250 milliwatts to rated output.
Continuous RMS power output (reference):
150 + 150 W
(6 ohms at 1 kHz, 10% THD)
Total harmonic distortion less than 0.09%
(6 ohms at 1 kHz, 70W)
Inputs
VIDEO (MD) IN (phono jacks):
voltage 250/450 mV, impedance 47 kilohms
AUDIO IN (phono jacks): 450 mV, impedance 47 kilohms
Outputs
VIDEO OUT (phono jacks):
max. output level 1Vp-p, unbalanced, Sync
negative, load impedance 75 ohms
PHONES (stereo phone jack):
accepts headphones of 8 ohms or more
SPEAKER: accepts impedance of 6 to 16 ohms
CD player section
System Compact disc and digital audio system
Laser Semiconductor laser
(CD: λ=780 nm)
Emission duration:
continuous
Frequency response CD: 20 Hz – 20 kHz
(±0.5 dB)
Wavelength 780 – 790 nm
Signal-to-noise ratio More than 90 dB
Dynamic range More than 90 dB
OPTICAL OUT (CD)
(Square optical connector jack, rear panel)
Wavelength 660 nm
Output level –18 dBm
Tape deck section
Recording system 4-track 2-channel stereo
Frequency response 40 – 13,000 Hz (±3dB),
using Sony TYPE I
cassettes
— Continued on next page —
9-877-216-04
2005E02-1
© 2005.05
MiNi Hi-Fi COMPONENT SYSTEM
Sony Corporation
Audio Group
Published by Sony Engineering Corporation
HCD-GSX75
Ver 1.1 2003.09
Tuner section
FM stereo, FM/AM superheterodyne tuner
FM tuner section
Tuning range 87.5 – 108.0 MHz
Antenna FM lead antenna
Antenna terminals 75 ohms unbalanced
Intermediate frequency 10.7 MHz
AM tuner section
Tuning range 530 – 1,710 kHz
(with the tuning interval
set at 10 kHz)
531 – 1,710 kHz
(with the tuning interval
set at 9 kHz)
Antenna AM loop antenna, external antenna terminal
Intermediate frequency 450 kHz
TABLE OF CONTENTS
1. SERVICING NOTES ······················································· 4
2. GENERAL ·········································································· 5
3. DISASSEMBLY ································································ 7
3-1. Top Cabinet ··································································· 8
3-2. Front Cabi ASSY ··························································· 8
3-3. Back Panel ASSY ·························································· 9
3-4. Main Board ···································································· 9
3-5. Amp Board ·································································· 10
3-6. Power Board ································································ 10
3-7. Holder (LED-S), Middle (R), Power Bracket ············· 11
3-8. CD Mechanism Deck (CDM64C-K1BD47B) ············ 11
3-9. Base Unit (BU-K1BD47B),
D-Sensor (OUT) Board, T-Sensor Board ···················· 12
3-10. D-Sensor (IN) Board, Load SW Board,
LT Motor Board ··························································· 12
3-11. CD LED Board ···························································· 13
3-12. BU Holder ASSY ························································ 13
3-13. CD Board, Optical Pick-up (KSM-213BFN) ·············· 14
3-14. RX-Base PC Board ASSY,
Mechanical Deck (CMAL1Z234A),
Cassette Holder ··························································· 14
3-15. Game Board, H/P Board ·············································· 15
3-16. Display Board ······························································ 15
3-17. KEY (2) Board, CD Sync Button ································ 16
3-18. KEY Board, Wireless Board ········································ 16
4. TEST MODE ···································································· 17
5. MECHANICAL ADJUSTMENTS ····························· 18
6. ELECTRICAL ADJUSTMENTS ······························ 18
General
Power requirements: 120 V AC, 60 Hz
Power consumption: 150 W
Dimensions (w/h/d) incl. projecting parts and controls Amplifier/Tuner/
Tape/CD section:
Approx. 280 x 326 x 490 mm
Mass: Approx. 11.4 kg
Supplied accessories Remote (1)
size AA (R6) batteries (2)
AM loop antenna (1)
FM lead antenna (1)
Design and specifications are subject to change
without notice.
7. DIAGRAMS
7-1. Circuit Boards Location ·············································· 22
7-2. Block Diagrams ··························································· 23
– CD Section – ···························································· 23
– Tuner/Tape Deck Section – ······································ 24
– INPUT/EVR Section – ············································· 25
– Amp Section – ·························································· 26
– Display/Power Supply Section – ······························ 27
7-3. Printed Wiring Board – CD Section – ························ 28
7-4. Schematic Diagram – CD Section – ··························· 29
7-5. Printed Wiring Board
– CD Motor/Sensor Section – ····································· 30
7-6. Schematic Diagram
– CD Motor/Sensor Section – ····································· 31
7-7. Printed Wiring Board – Main Section – ····················· 32
7-8. Schematic Diagram – Main Section (1/3) – ··············· 33
7-9. Schematic Diagram – Main Section (2/3) – ··············· 34
7-10. Schematic Diagram – Main Section (3/3) – ··············· 35
7-11. Printed Wiring Board – Amp Section – ······················ 36
7-12. Schematic Diagram – Amp Section –························· 37
7-13. Printed Wiring Board – Display Section – ················· 38
7-14. Schematic Diagram – Display Section – ···················· 39
7-15. Printed Wiring Board – Key Section – ······················· 40
7-16. Schematic Diagram – Key Section – ·························· 41
7-17. Printed Wiring Board – Power Section – ··················· 42
7-18. Schematic Diagram – Power Section – ······················ 43
7-19. IC Block Diagrams ······················································ 44
7-20. IC Pin Function Description ········································ 46
8. EXPLODED VIEWS
8-1. General Section ··························································· 51
8-2. Front Panel Section ····················································· 52
8-3. Chassis Section ···························································· 53
8-4. Mechanism Deck Section-1 (CDM64C-K1BD47B) ··· 54
8-5. Mechanism Deck Section-2 (CDM64C-K1BD47B) ··· 55
8-6. Base Unit Section (BU-K1BD47B) ···························· 56
9. ELECTRICAL PARTS LIST ······································· 57
2
HCD-GSX75
r
Notes on chip component replacement
• Never reuse a disconnected chip component.
• Notice that the minus side of a tantalum capacitor may be damaged by heat.
Flexible Circuit Board Repairing
• Keep the temperature of the soldering iron around 270 ˚C during
repairing.
• Do not touch the soldering iron on the same conductor of the
circuit board (within 3 times).
• Be careful not to apply force on the conductor when soldering or
unsoldering.
SAFETY CHECK-OUT
After correcting the original service problem, perform the following
safety check before releasing the set to the customer:
Check the antenna terminals, metal trim, “metallized” knobs, screws,
and all other exposed metal parts for AC leakage.
Check leakage as described below.
LEAKAGE TEST
The AC leakage from any exposed metal part to earth ground and
from all exposed metal parts to any exposed metal part having a
return to chassis, must not exceed 0.5 mA (500 microamperes.).
Leakage current can be measured by any one of three methods.
1. A commercial leakage tester, such as the Simpson 229 or RCA
WT-540A. Follow the manufacturers’ instructions to use these
instruments.
2. A battery-operated AC milliammeter. The Data Precision 245
digital multimeter is suitable for this job.
3. Measuring the voltage drop across a resistor by means of a VOM
or battery-operated AC voltmeter. The “limit” indication is 0.75
V, so analog meters must have an accurate low-voltage scale.
The Simpson 250 and Sanwa SH-63Trd are examples of a
passive VOM that is suitable. Nearly all battery operated digital
multimeters that have a 2 V AC range are suitable. (See Fig. A)
CAUTION
Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous
radiation exposure.
NOTES ON HANDLING THE OPTICAL PICK-UP
BLOCK OR BASE UNIT
The laser diode in the optical pick-up block may suffer electrostatic
break-down because of the potential difference generated by the
charged electrostatic load, etc. on clothing and the human body.
During repair, pay attention to electrostatic break-down and also
use the procedure in the printed matter which is included in the
repair parts.
The flexible board is easily damaged and should be handled with
care.
NOTES ON LASER DIODE EMISSION CHECK
The laser beam on this model is concentrated so as to be focused on
the disc reflective surface by the objective lens in the optical pickup block. Therefore, when checking the laser diode emission,
observe from more than 30 cm away from the objective lens.
LASER DIODE AND FOCUS SEARCH OPERATION
CHECK
Carry out the “S curve check” in “CD section adjustment” and check
that the S curve waveforms is output three times.
To Exposed Metal
Parts on Set
AC
1.5 k
0.15 µF
Fig. A. Using an AC voltmeter to check AC leakage.
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK 0 OR DOTTED LINE WITH
MARK 0 ON THE SCHEMATIC DIAGRAMS AND IN THE PARTS
LIST ARE CRITICAL TO SAFE OPERATION. REPLACE THESE
COMPONENTS WITH SONY PARTS WHOSE PART NUMBERS
APPEAR AS SHOWN IN THIS MANUAL OR IN SUPPLEMENTS
PUBLISHED BY SONY.
Ω
Earth Ground
voltmete
(0.75 V)
ATTENTION AU COMPOSANT AYANT RAPPORT
À LA SÉCURITÉ!
LES COMPOSANTS IDENTIFÉS PAR UNE MARQUE 0 SUR LES
DIAGRAMMES SCHÉMATIQUES ET LA LISTE DES PIÈCES SONT
CRITIQUES POUR LA SÉCURITÉ DE FONCTIONNEMENT. NE
REMPLACER CES COMPOSANTS QUE PAR DES PIÈSES SONY
DONT LES NUMÉROS SONT DONNÉS DANS CE MANUEL OU
DANS LES SUPPÉMENTS PUBLIÉS PAR SONY.
3
HCD-GSX75
SECTION 1
SERVICING NOTES
CD-TEXT TEST DISC
This unit is able to display the test data (character information)
written in the CD on its fluorescent indicator tube.
The CD-TEXT TEST DISC (TGCS-313: J-2501-126-A) is used
for checking the display.
To check, perform the following procedure.
Checking Method:
1. Press the I/1 button to turn the power on, set the disc to the
disc table with the “test disc” label facing right, and chuck the
disc.
2. Press the [CD] button to set CD function, and press the bB button to
playback the disc.
3. The following will be displayed on the liquid crystal display.
Display : 1KHZ/0dB/L R
4. Pressing the [-- ] or [ +] button, select the track. The text
data of each track will be displayed.
For details of the displayed contents for each track, refer to “Table
1: CD-TEXT TEST DISC TEXT Data Contents”.
Restrictions in CD-TEXT Display
In this unit, some special characters will not be displayed properly.
These will be displayed as a space or a character resembling it.
Table 1: CD-TEXT TEST DISC TEXT Data Contents
.>
(TRACKS No. 1 to 20: Normal Characters)
CLEANING OBJECTIVE LENS OF OPTICAL PICK-UP
• In cleaning the objective lens of optical pick-up, be sure the
following below.
2
Remove the
magnet assy.
optical pick-up
bracket (top 60) hole
A
3
Put a cotton bud into
the hole on the bracket
(top 60) and clean the
OP lens.
Note 1. In cleaning the lens, do not apply an excessive force.
As the optical pick-up is vulnerable, application of excessive
force could damage the lens holder.
Note 2. In cleaning, do not use a cleaner other than exclusive cleaning
liquid (KK-91 or isopropyl alcohol).
Note 3. Wipe the objective lens spirally from center toward outside. (See
Figure A)
1
Open the torsion holder
(magnet) in direction of
A
arrow
.
TRACK
No.
1 1kHz/0dB/L&R
2 20Hz/0dB/L&R
3 40Hz/0dB/L&R
4 100Hz/0dB/L&R
5 200Hz/0dB/L&R
6 500Hz/0dB/L&R
7 1kHz/0dB/L&R
8 5kHz/0dB/L&R
9 7kHz/0dB/L&R
10 10kHz/0dB/L&R
11 16kHz/0dB/L&R
12 18kHz/0dB/L&R
13 20kHz/0dB/L&R
14 1kHz/0dB/L&R
15 1kHz/–1dB/L&R
16 1kHz/–3dB/L&R
17 1kHz/–6dB/L&R
18 1kHz/–10dB/L&R
19 1kHz/–20dB/L&R
20 1kHz/–60dB/L&R
Displayed Contents
(Figure A)
Note: Track No. 21 to 99 are not displayed.
4
MAIN UNIT
ALPHABETICAL ORDER
A – H
ALBM + qs
ALBM – wj
AUDIO IN jack w;
CD wh
CD SYNC 0
CLEAR wk
DISC SELECT ws
DISPLAY 7
Display window 2
ENTER wl
FM MODE/REPEAT 9
GAME qg
GAME MIXING qa
SECTION 2
GENERAL
I – Z
ILLUMINATION 6
KEYBOARD INPUT jack ql
MENU e;
PHONES jack qk
PLAY MODE/DIRECTION 8
POWER ILLUMINATOR wd
Remote sensor ea
TAPE qd
Tape deck 3
TUNER/BAND wg
VIDEO (MD) qf
VIDEO IN jack wa
VOLUME wf
HCD-GSX75
This section is extracted
from instruction manual.
BUTTON DESCRIPTIONS
?/1 (power) 1
Z PUSH (tape deck) 3
nN (play) 4
X (pause) 4
x (stop) 4
REC PAUSE/START 5
Z PUSH (front cover) qh
m (rewind) qj
M (fast forward) qj
. (go back) qj
> (go forward) qj
5
HCD-GSX75
REMOTE CONTROL
ALPHABETICAL ORDER
A – Q
ALBM +/– qfwa
CD wl
CLEAR 0
CLOCK/TIMER SELECT 2
CLOCK/TIMER SET 3
DISC +/– qgw;
DISPLAY qa
ENTER wg
GAME wj
GAME MIXING 9
GROOVE qj
MENU wh
PLAY MODE 6
PRESET +/– qswd
PRESET EQ qh
R – Z
REPEAT 8
SLEEP 1
SURROUND ql
TAPE 5
TUNER/BAND e;
TUNING +/– qdws
VIDEO (MD) wk
VOL +/– qk
WIRELESS 7
This section is extracted
from instruction manual.
BUTTON DESCRIPTIONS
?/1 (power) 4
nN (play) wf
X (pause) wf
x (stop) wf
. (go back) wd
m (rewind) ws
M (fast forward) qd
> (go forward) qs
NOTES FOR THE SUPPLIED
REMOTE
* The WIRELESS button is not
available for MHC-GSX75.
6
• This set can be disassembled in the order shown below.
SET
TOP CABINET
FRONT CABI ASSY
BACK PANEL ASSY
MAIN BOARD
MECH
SECTION 3
DISASSEMBLY
DECK (CMAL1Z234A),
CASSETTE HOLDER
HCD-GSX75
Ver 1.1 2003.09
AMP BOARD
POWER BOARD
HOLDER (LED-S),
MIDDLE(R) BRACKET ,
POWER BRACKET
CD MECHANISM DECK
(CDM64C-K1BD47B)
BASE UNIT (BU-K1BD47B),
D-SENSOR (OUT) BOARD,
T-SENSOR BOARD
D-SENSOR (IN) BOARD,
LOAD SW BOARD,
LT MOT OR BOARD
DISPLAY
KEY(2)
BOARD, CD SYNC BUTTON
CD LED BOARD
BU HOLDER ASSY
OPTOCAL PICK-UP (KSM-213BFN)
BOARD
CD BOARD,
GAME BOARD, H/P BOARD
KEY BOARD
7
HCD-GSX75
Note: Follow the disassembly procedure in the numerical order given.
3-1. TOP CABINET
6
Three screws
5
(BVTP3
8
Panel side (L)
×
10)
Tw o screws
(BVTP3
×
10)
7
qd
Top
qs
cabinet
9
Three screws
(BVTP3
3
×
10)
0
Wire (Flat type) (CN309 )
qa
Connector (CN441)
4
Panel side (R)
2
Tw o screws
(BVTP3
×
10)
3-2. FRONT CABI ASSY
8
Screw (BVTP3 ×8)
qs
Screw (KTP3 ×8)
Lugs
2
Connector (CN705)
1
Connector (CN358)
qd
Three screws
1
(BVTP3
3
Wire (Flat type) (CN720)
4
Wire (Flat type)
(CN316)
5
Wire (Flat type)
(CN314)
×
10)
qf
Front cabi ASSY
6
Connector (CN306)
7
Connector (CN310)
0
Four screws
(BVTP3
Lugs
qa
Screw (KTP3 ×8)
×
8)
9
Screw (BVP3 ×8)
8
3-3. BACK PANEL ASSY
)
d
1
Connector (CN356)
2
Connector (CN351)
4
DC Fan (M351)
3
Tw o screws (BVTP 3x10)
qs
Back panel ASSY
7
5
8
HCD-GSX75
Three screws (BVTP 3x10)
Tw o screws (BVTP 3x10)
Four screws (BVTP 3x10)
9
Screw (BVTP 3x10)
0
Four screws (BVTP 3x10
qa
Tw o screws (BVTP 3x10)
3-4. MAIN BOARD
1
Connector (CN354)
2
Wire (Flat type)
(CN305)
Lug
6
SPK board
4
Connector (CN308)
3
Wire (Flat type)
(CN311)
8
Screw
(BVTP3 ×8)
Lug
7
Screw
(BVTP3 × 8)
5
Connector (CN307)
6
Connector (CN301)
0
MAIN boar
9
Screw
(BVTP3 ×8)
9
HCD-GSX75
)
d
3-5. AMP BOARD
1
Connector (CN353)
2
Tw o screws
(BVTP3
×
8)
4
Tw o screws (BVTP3 ×8)
3
Tw o screws (BVTP3 ×8
5
AMP board
3-6. POWER BOARD
1
Tw o screws
(BVTP4
2
Tw o screws
(BVTP4
×
8)
×
8)
3
POWER boar
Lug
10
3-7. HOLDER (LED-S), MIDDLE (R) BRACKET, POWER BRACKET
t
)
3
1
Tw o screws
(BVTP3
×
8)
Three screws
(BVTP3
×
8)
5
Middle (R) bracket
HCD-GSX75
Ver 1.1 2003.09
4
Tw o screws
(BVTP3
8
×
8)
7
Tw o screws
(BVTP3
Three screws
(BVTP3
9
Power bracke
×
8)
×
8)
2
Holder (LED-S)
3-8. CD MECHANISM DECK (CDM64C-K1BD47B)
1
Screw (M3 ×12)
2
Ta bl e (60)
6
screw (BVTP3 ×8)
7
CD mechanism deck
(CDM64C-K1BD47B)
Lower chassis
6
Four screws
×
(BVTP3
8)
4
Tw o screws
(BVTP3
3
Screw
×
6)
8)
5
Four screws
(BVTP3
(PSW3
×
×
8
11
HCD-GSX75
3-9. BASE UNIT (BU-K1BD47B), D-SENSOR (OUT) BOARD, T-SENSOR BOARD
4
Screw (BVTP3 ×8)
5
D-SENSOR (OUT) board
2
Bracket (top 60)
1
Three screws
×
(BVTP3
8)
3
Base unit
(BU-K1BD47B)
6
Three screws
(BVTP3
×
8)
7
T- SENSOR board
3-10. D-SENSOR (IN) BOARD, LOAD SW BOARD, LT MOTOR BOARD
5
Belt
6
Belt
3
Tw o screws
(BVTP3 ×8)
4
D-SENSOR (IN) board
*
Cautions of an assembly
Pulley (60)
Motor (60) ASSY (M442)
Motor (60) ASSY (M441)
9
Screw (BVTP3 ×8)
12
1
Screw (BVTP3 ×8)
2
Brackcet (d-sensor)
8
LT MOTOR board
7
Three screws
(BVTP3 ×8)
0
LOAD SW board
3-11. CD LED BOARD
)
3
CD LED board
HCD-GSX75
Opens to right and left and
CD LED BOARD
is removed upwards
from a slot.
1
2
3-12. BU HOLDER ASSY
5
BU holder ASSY
1
Tension spring (F1)
2
Tension spring (F-2)
4
Tw o screws
(PTP2.6 ×8)
3
Tw o screws
(PTP2.6 ×8
13
HCD-GSX75
Ver 1.1 2003.09
3-13. CD BOARD, OPTICAL PICK-UP (KSM-213BFN)
6
CD board
1
Remove two
solders.
7
Optical pick-up (KSM-213BFN)
5
Wire (Flat type)
(CN102)
3
4
2
Remove two solders.
Screw (P2 ×5)
3-14. RX-BASE PC BOARD ASSY, MECHANICAL DECK (CMAL1Z234A), CASSETTE HOLDER
8
Cassette holder
5
Cassette spring
4
3
7
14
2
Mech
deck (CMAL1Z234A)
1
Four screws
(BVTP3
6
D
amper
Lug
×
8)
3-15. GAME BOARD, H/P BOARD
HCD-GSX75
Wire retainer pwb
Harness
Front cabinet
1
2
GAME board
5
H/P board
Tw o screws
(BVTP2.6
4
Retainer H/P
×
8)
3
Tw o screws
(BVTP2.6
×
8)
3-16. DISPLAY BOARD
3
Wire (Flat type) (CN714 )
4
1
Connector (2p)
SW701
Three screws
(BVTP2.6 ×10)
2
Connector (CN713)
15
HCD-GSX75
)
s
3-17. KEY (2) BOARD, CD SYNC BUTTON
3
Connector (CN706)
1
Tw o screws
(BVTP2.6
4
×
8)
2
KEY (2) board
5
Tw o screws
(BVTP3 ×10
6
CD sync button
Screw(BVTP3 ×10)
3-18. KEY BOARD, WIRELESS BOARD
7
Volume cover
8
Volume indicator
2
Three claws
qa
KEY board
9
Four screws
(BVTP3
×
10)
0
Three screw
(BVTP3 ×10)
16
1
Disc knob
4
3
Volume knob
Nut
5
6
Washer
Volume rubber
SECTION 4
TEST MODE
HCD-GSX75
[Panel Test Mode]
Procedure:
1. Press three buttons of x , [MENU], and [DISPLAY] simulta-
neously.
2. LEDs and fluorescent indicator tube are all turned on.
3. Press the [MENU] button and go to the version display mode.
Press the m button and go to the key and jog test mode.
4. To release from these mode, press three buttons in the same
manner as step 1, or disconnect the power cord.
– Version display mode –
In the version display mode, each time the [MENU] button is
pressed, the display changes in the order of MC, GC, CD, CDD,
CDM A, CDM B, BDA, BDB, ST, TA, TM and TC.
Press the . button to display the date of the software.
– Key and jog test mode –
In the key check mode, the fluorescent indicator tube displays
“K 0 J0 V0”. Each time a button is pressed, “K” value increases without I/1 and [DISPLAY] buttons. However, once
a button is pressed, it is no longer taken into account.
“J” value increases like 1, 2, 3 ... if turn the [DISC SELECT]
dial clockwise, or it decreases like 0, 9, 8 ... if turn the
[DISC SELECT] dial counterclockwise.
“V” value increases like 1, 2, 3 ... if turn the [VOLUME] knob
clockwise, or it decreases like 0, 9, 8 ... if turn the [VOLUME]
knob counterclockwise.
[Cold Reset]
• The cold reset clears all data including preset data stored in the
RAM to initial conditions. Execute this mode when returning
the set to the customer.
Procedure:
1. Turn the power ON or set to the DEMO mode.
2. Press three buttons of x , [CLEAR], and [DISPLAY] simultaneously.
3. The set is reset, and becomes DEMO mode.
[CD Ship Mode and RAM Initialize]
•This mode moves the optical pick-up to the position durable to
vibration, and initializes the RAM. Use this mode when returning the set to the customer after repair.
Procedure:
1. Press the I/1 button to turn the power ON and select the function CD.
2. Press three buttons of
taneously.
3. The set is turn the power off and initializes the RAM automatically. A message “LOCK” is displayed on the fluorescent
indicator tube, and the CD delivery mode is set.
[ENTER], [REPEAT], and X simul-
[CD Service Mode]
•This mode can run the CD sled motor optionally. Use this mode,
for instance, when cleaning the optical pick-up.
Procedure:
1. Press the I/1 button to turn the power ON.
2. Select the function “CD”.
3. Press three buttons of [ENTER], M , and
[PLAY MODE] simultaneously.
4. Set to the Sled Servo mode.
5. With the CD in stop status, press the M button to move the
optical pick-up to outside track and display “SLED OUT”, or
press the m button to move the optical pick-up to inside
track and display “SLED IN”.
6. To exit from this mode, perform as follows.
1) Move the optical pick-up to the most inside track.
2) Press three buttons of x , [CLEAR], and [DISPLAY]
simultaneously. (cold reset)
Notes: •Always move the optical pick-up to most inside track when
exiting from this mode. Otherwise, a disc will not be unloaded.
• Do not run the sled motor excessively, otherwise the gear can
be chipped.
[VACS Test Mode]
•This mode is used to switch on and off the VACS (Variable Attenuation Control System).
Procedure:
1. Press the I/1 button to turn the set on.
2. To enter the test mode, press the two buttons [ENTER] , [PLAY
MODE] and X simultaneously.
3. The message “VACS OFF” or “VACS ON” appears.
4. To exit from this mode, press the I/1 button to turn the set
off.
[Function Selection Mode]
•This mode is used to select the input VIDEO or input MD.
Procedure:
1. Turn off the set.
2. Press the two buttons x and [VIDEO $MD%] simultaneously.
3. The message “VIDEO” or “MD” appears.
4. To exit from this mode, press the I/1 button to turn the set
off.
[AM Channel Step 9 kHz/10 kHz Selection Mode]
•The AM tuning interval can be changed over 9 kHz or 10 kHz.
Procedure:
1. Press the I/1 button to turn the power on.
2. Select the function “TUNER”, and press the [TUNER/BAND]
button to select the BAND “AM”.
3. Press the I/1 button to turn the power off.
4. Press the [ENTER] and I/1 buttons simultaneously.
5. Either the message “AM 9k STEP” or “AM 10k STEP” appears, and thus the channel step is changed over.
17
HCD-GSX75
SECTION 5
MECHANICAL ADJUSTMENTS
SECTION 6
ELECTRICAL ADJUSTMENTS
• TAPE MECHANISM DECK SECTION
Precaution
1. Clean the following parts with a denatured alcohol-moistened
swab:
record/playback heads pinch rollers
erase head rubber belts
capstan idlers
2. Demagnetize the record/playback head with a head demagnetizer.
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
5. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
Torque Measurement
Mode
FWD
FWD /REV
back tension
REV
Tor que meter
CQ-102C
CQ-102C
CQ-102RC
Meter reading
2.44 mN • m to 8.33 mN • m
30 to 85 g • cm
(0.42 – 1.17 oz • inch)
0.14 mN • m to 0.59 mN • m
2 to 6 g • cm
(0.03 – 0.08 oz • inch)
2.94 mN • m to 7.84 mN • m
31 to 71 g • cm
(0.43 – 0.98 oz • inch)
DECK SECTION
Precaution
1. Demagnetize the record/playback head with a head demagnetizer.
2. Do not use a magnetized screwdriver for the adjustments.
3. After the adjustments, apply suitable locking compound to the
parts adjust.
4. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
5. The adjustments should be performed in the order given in
this service manual. (As a general rule, playback circuit adjustment should be completed before performing recording
circuit adjustment.)
6. The adjustments should be performed for both L-CH and RCH.
7. Switches and controls should be set as follows unless otherwise specified.
•Test Tape
Tape Signal Used for
P-4-A100 10 kHz, – 10 dB Azimuth Adjustment
WS-48B 3 kHz, 0 dB Tape Speed Check
0 dB = 0.775 V
FF/REW
CQ-201B
6.86 mN • m to 20.6 mN • m
71 to 210 g • cm
(0.98 – 2.91 oz • inch)
18
HCD-GSX75
)
Record/Playback Head Azimuth Adjustment
Procedure:
1. Mode: Playback (FWD)
test tape
P-4-A100
(10 kHz, – 10 dB)
SPK board
SPEAKER terminal (J357
L-CH, R-CH
set
level meter
+
–
2. Turn the adjustment screw and check output peaks. If the peaks
do not match for L-CH and R-CH, turn the adjustment screw
so that outputs match within 1dB of peak.
Output
level
within
1dB
L-CH
peak
R-CH
peak
within
1dB
Screw
position
L-CH
peak
Screw
position
R-CH
peak
3. Mode: Playback
Adjustment Location: Record/Playback/Erase Head
Head azimuth
adjustment screw
Tape Speed Check
Mode: Playback
test tape
WS-48B
(3 kHz, 0 dB)
set
frequency counter
+
–
SPK board
test tape
P-4-A100
(10 kHz, – 10 dB)
L-CH
set
R-CH
in phase 45°90°135°180
SPEAKER terminal (J357)
L-CH
R-CH
waveform of oscilloscope
good
oscilloscope
wrong
H
V
°
4. Reapeat step 1 to 3 in playback (REV) mode.
5. After the adjustments, apply suitable locking compound to the
parts adjusted.
SPK board
SPEAKER terminal (J357)
L-CH, R-CH
1. Insert the WS-48B into the deck.
2. Press the bB button on the deck.
3. Confirm that the frequency counter reads 3,000 ± 90 Hz.
Sample value of Wow and Flutter: 0.3% or less W.RMS (JIS)
(WS-48B)
19
HCD-GSX75
+
–
CD board
TP (RFAC)
TP (DVC)
oscilloscope
CD SECTION
Note:
1. CD Block is basically designed to operate without adjustment. Therefore, check each item in order given.
2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
3. Use an oscilloscope with more than 10MΩ impedance.
4. Clean the object lens by an applicator with neutral detergent when the
signal level is low than specified value with the following checks.
S-curve Check
Connection:
oscilloscope
CD board
TP (FE1)
TP (DVC)
Procedure:
1. Connect an oscilloscope to test point TP (FE1) and TP (DVC)
on the CD board.
2. Turn the power on.
3. Put the disc (YEDS-18) in and turned power switch on again
and actuate the focus search. (actuate the focus search when
disc table is moving in and out)
4. Check the oscilloscope waveform (S-curve) is symmetrical
between A and B. And confirm peak to peak level within 2 ± 1
Vp-p.
+
–
RFAC Level Check
Connection:
Procedure:
1. Connect an oscilloscope to test point TP (RFAC) and TP (DVC)
on the CD board.
2. Turn the power on.
3. Put the disc (YEDS-18) in to playback the number five track.
4. Confirm that oscilloscope waveform is clear and check RFAC
signal level is correct or not.
Note: A clear RFAC signal waveform means that the shape “◊” can be
clearly distinguished at the center of the waveform.
RFAC signal waveform
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level: 1.35 ± 0.4 Vp-p
S-curve waveform
symmetry
A
B
Note: •Try to measure several times to make sure than the ratio of A : B
or B : A is more than 10 : 7.
•Take sweep time as long as possible and light up the
brightness to obtain best waveform.
within 2
±
1 Vp-p
Checking Location: CD board (Conductor side)
(See page 21.)
Checking Location: CD board (Conductor side)
(See page 21.)
20
HCD-GSX75
E-F Balance Check
Connection:
oscilloscope
CD board
TP (TE1)
TP (DVC)
+
–
Procedure:
1. Connect an oscilloscpe to test point TP (TE1) and TP (DVC)
on the CD board.
2. Turn the power on.
3. Select the function “CD”.
4. Press three buttons of [ENTER], M , and
[PLAY MODE] simultaneously to set the CD service mode.
5. Put the disc (YEDS-18) in to playback the number five track.
6. Press the . button. The message “TRAVERSE” is
displayed. (The tracking servo and the sledding servo are turned
OFF)
7. Check the level B of the oscilliscope's waveform and the A
(DC voltage) of the center of the Traverse waveform.
Confirm the following :
A/B x 100 = less than ± 22%
Tr averse Waveform
Center of
the waveform
Checking Location:
– CD BOARD (Conductor Side) –
TP (FE1)
TP (TE1)
TP (DVC)
IC101
TP (RFAC)
IC103
IC104
B
0V
level: 1.15 ± 0.5 Vp-p
A (DC
voltage)
8. Press the . button. The message “TRAVERSE” is
displayed. (The tracking servo and sledding servo are turned
ON)
Confirm the C (DC voltage) is almost equal to the A (DC
voltage) is step 5.
9. To exit from this mode, perform as follows.
1) Move the optical pick-up to the most inside track.
2) Press three buttons of x , [CLEAR], and [DISPLAY]
simultaneously. (cold reset)
Notes: •Always move the optical pick-up to most inside track when
0V
exiting from this mode. Otherwise, a disc will not be unloaded.
• Do not run the sled motor excessively, otherwise the gear can
be chipped.
Tr averse Waveform
C (DC
voltage)
Tr acking servo
Sled servo
OFF
Tr acking servo
Sled servo
Checking Location: CD board (Conductor side)
ON
21
Loading...