1
HCD-BX7/DX7/DX7J
SERVICE MANUAL
HCD-BX7/DX7/DX7J is the tuner, deck, CD and
amplifier section in MHC-BX7/DX7/DX7J.
SPECIFICATIONS
COMPACT DISC DECK RECEIVER
-- Continued on next page --
Model Name Using Similar Mechanism
NEW
CD Mechanism Type
CDM58-K2BD38
Base Unit Type
BU-K2BD38
Optical Pick-up Type
KSS-213DP
Model Name Using Similar Mechanism
NEW
Tape Transport Mechanism Type
TCM-230MWR11
CD
SECTION
TAPE DECK
SECTION
Photo: HCD-DX7
US Model
Canadian Model
AEP Model
UK Model
HCD-BX7
E Model
HCD-DX7/DX7J
Australian Model
HCD-DX7
2
SAFETY CHECK-OUT
(US model only)
After correcting the original service problem, perform the
following safety checks 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
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 microampers).
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 2V AC range are suitable. (See
Fig. A)
Fig. A. Using an AC voltmeter to check AC leakage.
0.15
µF
To Exposed Metal
Parts on Set
1.5k
AC
voltmeter
(0.75V)
Earth Ground
3
This appliance is classified as a CLASS 1 LASER product. The
CLASS 1 LASER PRODUCT MARKING is located on the rear
exterior.
Laser component in this product is capable
of emitting radiation exceeding the limit for
Class 1.
CAUTION
Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous radiation
exposure.
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 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.
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 pick-
up block. Therefore, when checking the laser diode emission,
observe from more than 30 cm away from the objective lens.
MODEL IDENTIFICATION
-- BACK PANEL --
TABLE OF CONTENTS
1. SERVICE NOTE ······························································· 4
2. GENERAL ·········································································· 5
3. DISASSEMBLY ································································ 7
4. TEST MODE ···································································· 12
5. MECHANICAL ADJUSTMENTS ····························· 16
6. ELECTRICAL ADJUSTMENTS ······························· 16
7. DIAGRAMS
7-1.
Circuit Board Location ····················································· 21
7-2.
Block Diagrams ································································ 22
7-3.
Printed Wiring Board BD Section ······························ 24
7-4.
Schematic Diagram BD Section ································· 25
7-5.
Printed Wiring Board Main Section ··························· 26
7-6.
Schematic Diagram Main (1/3) Section ····················· 27
7-7.
Schematic Diagram Main (2/3) Section ····················· 28
7-8.
Schematic Diagram Main (3/3) Section ····················· 29
7-9.
Printed Wiring Board Power AMP Section
(BX7 model) ····································································· 30
7-10. Schematic Diagram Power AMP Section
(BX7 model) ····································································· 31
7-11. Printed Wiring Board Power AMP Section
(DX7, DX7J model) ························································· 32
7-12. Schematic Diagram Power AMP Section
(DX7, DX7J model) ························································· 33
7-13. Printed Wiring Board Panel Section ··························· 34
7-14. Schematic Diagram Panel Section ····························· 35
7-15. Printed Wiring Board Leaf SW Section ···················· 36
7-16. Schematic Diagram Leaf SW Section ························ 37
7-17. Printed Wiring Board Driver Section ························· 38
7-18. Schematic Diagram Driver Section ···························· 39
7-19. Printed Wiring Board Trans Section
(BX7 model) ····································································· 40
7-20. Schematic Diagram Trans Section
(BX7 model) ····································································· 41
7-21. Printed Wiring Board Trans Section
(DX7, DX7J model) ························································· 42
7-22. Schematic Diagram Trans Section
(DX7, DX7J model) ························································· 43
7-23. IC Pin Function Description ············································· 44
7-24. IC Block Diagrams ··························································· 46
8. EXPLODED VIEWS
8-1.
Main Section ····································································· 49
8-2.
Panel Section ···································································· 50
8-3.
Main Board Section ·························································· 51
8-4.
Tape Mechanism Section ·················································· 52
8-5.
CD Mechanism Section ···················································· 53
9. ELECTRICAL PARTS LIST ······································· 54
PARTS No.
· Abbreviation
CND : Canadian model
AUS
: Australian model
G
: German model
EA
: Saudi Arabia model
MY
: Malaysia model
SP
: Singapore model
TH
: Thai model
KR
: Korea model
MX
: Mexican model
AR
: Argentina model
E2
: Central and
South AMERICA
E3
: Middle and Near East
MODEL
AED, AEP, CIS, UK, G, AUS,
KR, MX, TH models
AR, E, EA, SP, TW, MY models
US, CND models
DX7J model
PARTS No.
4-225-040-1s
4-225-040-2s
4-225-040-3s
4-228-592-3s
4
SECTION 1
SERVICE NOTE
Screw hole
Attach the panel board with
six screws (+BVTP 2.6
× 8 )
after the board is removed once.
Do not tighten the screws excessively.
1
Cut the eleven melted-connection points with a cutting plier.
Note for installing the panel board
2
Panel board
Hot melt
5
SECTION 2
GENERAL
1
DISC SKIP EX-CHANGE button
2
DISC 1 button and indicator
3
DISC 2 button and indicator
4
DISC 3 button and indicator
5
Z OPEN/CLOSE button
6
EDIT, TUNER MOMERY button
7
PLAY MODE, STEREO/MONO button
8
REPEAT, DOLBY NR button
9
DIRECTION knob (EXCEPT AEP, G, UK, CIS)
DIRECTION, PTY knob (AEP, G, UK, CIS model)
q;
SURROUND button
qa
VOLUME knob
qs
PHONES jack
qd
ENTER button
qf
REC PAUSE/START button and indicator
qg
CD SYNC HI-DUB button
qh
LOOP button (BX7 model)
LOOP, KARAOKE PON button (DX7, DX7J model)
qj
MIC jack (DX7, DX7J model)
qk
MIC LEVEL knob (DX7, DX7J model)
ql
V-GROOVE button and indicator
w;
CURSOL button and indicator
wa
GROOVE button
ws
EQ EDIT button
wd
SPECTRUM button
wf
DISPLAY button
wg
?/1 button and indicator
wh
TUNER/BAND button
wj
MD (VIDEO) button
wk
Y button
wl
> + button
e;
X button
ea
. button
es
x button
ed
TAPE A/B button
ef
CD button
eg
Function indicator
Photo: HCD-BX7
12 3 4
5
6
7
8
qa
qs
qd
qf
qg
qh
w;
ws
ed
ef
wh
wj
wk
wl
e;
ea
9
q;
wa
ql
wd
wf
wg
es
qk
qj
eg