Page 1
MX-G500
1-2
1. This design of this product contains special hardware and many circuits and components specially for safety
purposes. For continued protection, no changes should be made to the original design unless authorized in
writing by the manufacturer. Replacement parts must be identical to those used in the original circuits. Services
should be performed by qualified personnel only.
2. Alterations of the design or circuitry of the product should not be made. Any design alterations of the product
should not be made. Any design alterations or additions will void the manufacturer`s warranty and will further
relieve the manufacture of responsibility for personal injury or property damage resulting therefrom.
3. Many electrical and mechanical parts in the products have special safety-related characteristics. These
characteristics are often not evident from visual inspection nor can the protection afforded by them necessarily
be obtained by using replacement components rated for higher voltage, wattage, etc. Replacement parts which
have these special safety characteristics are identified in the Parts List of Service Manual. Electrical
components having such features are identified by shading on the schematics and by ( ) on the Parts List in
the Service Manual. The use of a substitute replacement which does not have the same safety characteristics
as the recommended replacement parts shown in the Parts List of Service Manual may create shock, fire, or
other hazards.
4. The leads in the products are routed and dressed with ties, clamps, tubings, barriers and the like to be
separated from live parts, high temperature parts, moving parts and/or sharp edges for the prevention of
electric shock and fire hazard. When service is required, the original lead routing and dress should be
observed, and it should be confirmed that they have been returned to normal, after re-assembling.
5. Leakage currnet check (Electrical shock hazard testing)
After re-assembling the product, always perform an isolation check on the exposed metal parts of the product
(antenna terminals, knobs, metal cabinet, screw heads, headphone jack, control shafts, etc.) to be sure the
product is safe to operate without danger of electrical shock.
Do not use a line isolation transformer during this check.
Plug the AC line cord directly into the AC outlet. Using a "Leakage Current Tester", measure the leakage
current from each exposed metal parts of the cabinet, particularly any exposed metal part having a return
path to the chassis, to a known good earth ground. Any leakage current must not exceed 0.5mA AC (r.m.s.).
Alternate check method
Plug the AC line cord directly into the AC outlet. Use an AC voltmeter having, 1,000 ohms per volt or more
sensitivity in the following manner. Connect a 1,500 10W resistor paralleled by a 0.15 F AC-type capacitor
between an exposed metal part and a known good earth ground.
Measure the AC voltage across the resistor with the AC
voltmeter.
Move the resistor connection to each exposed metal part,
particularly any exposed metal part having a return path to
the chassis, and meausre the AC voltage across the resistor.
Now, reverse the plug in the AC outlet and repeat each
measurement. Voltage measured any must not exceed 0.75 V
AC (r.m.s.). This corresponds to 0.5 mA AC (r.m.s.).
1. This equipment has been designed and manufactured to meet international safety standards.
2. It is the legal responsibility of the repairer to ensure that these safety standards are maintained.
3. Repairs must be made in accordance with the relevant safety standards.
4. It is essential that safety critical components are replaced by approved parts.
5. If mains voltage selector is provided, check setting for local voltage.
Good earth groundPlace this
probe on
each exposed
metal part. AC VOLTMETER
(Having 1000
ohms/volts,
or more sensitivity)
1500 10W 0.15 F AC TYPE
!
Burrs formed during molding may
be left over on some parts of the
chassis. Therefore, pay attention to
such burrs in the case of
preforming repair of this system.
In regard with component parts appearing on the silk-screen printed side (parts side) of the PWB diagrams, the
parts that are printed over with black such as the resistor ( ), diode ( ) and ICP ( ) or identified by the " "
mark nearby are critical for safety.
(This regulation does not correspond to J and C version.)
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1-3
MX-G500
Preventing static electricity
1. Grounding to prevent damage by static electricity
Electrostatic discharge (ESD), which occurs when static electricity stored in the body, fabric, etc. is discharged,
can destroy the laser diode in the traverse unit (optical pickup). Take care to prevent this when performing repairs.
2. About the earth processing for the destruction prevention by static electricity
In the equipment which uses optical pick-up (laser diode), optical pick-up is destroyed by the static electricity of
the work environment.
Be careful to use proper grounding in the area where repairs are being performed.
2-1 Ground the workbench
Ground the workbench by laying conductive material (such as a conductive sheet) or an iron plate over
it before placing the traverse unit (optical pickup) on it.
2-2 Ground yourself
Use an anti-static wrist strap to release any static electricity built up in your body.
3. Handling the optical pickup
1. In order to maintain quality during transport and before installation, both sides of the laser diode on the
replacement optical pickup are shorted. After replacement, return the shorted parts to their original condition.
(Refer to the text.)
2. Do not use a tester to check the condition of the laser diode in the optical pickup. The tester's internal power
source can easily destroy the laser diode.
4. Handling the traverse unit (optical pickup)
1. Do not subject the traverse unit (optical pickup) to strong shocks, as it is a sensitive, complex unit.
2. Cut off the shorted part of the flexible cable using nippers, etc. after replacing the optical pickup. For specific
details, refer to the replacement procedure in the text. Remove the anti-static pin when replacing the traverse
unit. Be careful not to take too long a time when attaching it to the connector.
3. Handle the flexible cable carefully as it may break when subjected to strong force.
4. It is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not turn it
Conductive material
(conductive sheet) or iron plate
(caption)
Anti-static wrist strap
Attention when CD mechanism assembly is decomposed
1. Remove the CD changer unit.
2. Remove the CD changer mechanism.
3. Solder is put up before the card wire is removed from the pickup unit
connector on the CD mechanism assembly.
(When the card wire is removed without putting up solder, the CD pick-up
assembly might destroy.)
4. Please remove solder after connecting the card wire with the pickup unit
connector when you install picking up in the substrate.
*Please refer to "Disassembly method" in the text for pick-up and how to
detach the CD mechanism assembly.
SolderingFig.1
Fig.2
Card wire Card wire
Picup unit
connector
Picup unit
connector CD changer unit
CD changer
mechanism
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MX-G500
1-38
HA12237 (JIC1) : Audio signal processor
1. Block diagram
REC OUT(L)
NC
ALC(L)
TEST
(Open for normal use)
IREF
ALC ON/OFF High/Normal A
(REC RETURN ON/OFF) Vcc
MUTE ON/OFF REC MUTE OFF/ON GND
ALCDET
A/ B
MUTE
120/60
(Norm/High)
REC OUT(R)
NC
NC
TAI(R)
EQOUT(R)
PB-EQ(R) ALC(R)
REC IN(R)
14
56
89
10 AB
7 3
2
Return SW
+
EQALC
PB OUT(R)
PB-NF2(R)
34
35
36
37
38
39
40 GNDREC
ReturnIN(L)
AIN(R)IN(R)
PB-NF1(R)
Return SW
NC30
31
32
33 RIP
AB
28
120/60
(Norm/High)
AIN(L) PB-NF1(L)
29
+
TAI(L)
EQOUT(L)
PB-NF2(L)PB-EQ(L)
21 22 23
24
25 26
27
MUTE
EQ
NC
PB OUT(L)REC IN(L)
11 1213 141516 17 181920
2. Pin function
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14 Symbol
PB-NF2(R)
PB-EQ(R)
EQOUT(R)
TAI(R)
PBOUT(R)
NC
RECIN(R)
NC
RECOUT(R)
ALC ON/OFF
High/Norm
A/B
MUTE ON/OFF Function
PB EQ feed back
NAB output
EQ output
Tape input
PB output
NC pin
REC-EQ input
NC pin
REC output
Mode control input
Mode control input
Mode control input
Mode control inputPin No.
15
16
17
18
19
20
21
22
23
24
25
26 Symbol
REC MUTE
OFF/ON
Vcc
GND
IREF
Test mode
RECOUT(L)
NC
RECIN(L)
NC
PBOUT(L) Function
Mode control input
Vcc pin
GND pin
Equalizer reference
current input
Test mode pin
REC output
NC pin
REC-EQ input
NC pin
PB outputPin No.
27
28
29
30
31
32
33
34
35
36
37
38
39
40 Symbol
TAI(L)
EQOUT(L)
PB-EQ(L)
PB-NF2(L)
PB-NF(L)
AIN(L)
RIP
BIN(L)
REC-RETURN
GND
BIN(R)
NC
AIN(R)
PB-NF1(R) Function
Tape input
EQ output
NAB output
PB EQ feed back
PB EQ feed back
PB A deck input
Ripple filter
PB B deck input
REC Return
GND pin
PB B deck input
NC pin
PB A deck input
PB EQ feed back
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MX-G500
D0
D1
CLK
CS
Vcc
S
GND
D24
D23
D22
D21
D20
D19
D18
D17
GND
M66010 (UIC2) : I/O control
1.Pin layout
2.Block diagram
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
1632
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17 DO
DI
CLK
CS
S
D24
D23
D22
D21
D20
D19
D18
D17D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
D12
D13
D14
D15
D16 D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
D12
D13
D14
D15
D16
1
2
3
4
5
6
7
8
9
10
16
32
31
30 CLOCK INPUT CLK
SET INPUT S
CHIP SELECT CS
INPUT
SERIAL DATA DI
INPUT
GND GNDVcc
DO SERIAL DATA
OUTPUT
PARALLEL
DATA I/OD1
D2
D3
D22
D23
D24
Control circuit
Shift register 1 DO
D24 D23 D22 D3 D2 D1
Q24 Q23 Q22 Q3 Q2 Q1
D24 D23 D22 D3 D2 D1
Q24 Q23 Q22 Q3 Q2 Q1
DI
Parallel output latch
Shift register 2
STK402-040 (AIC1) / STK402-090 (AIC2) : Power amp.
1.Pin layout
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
ch.1ch.2 +
_+
_
CH1
INCH1
NFNC Pre
VccBIAS CH1
VECH1
-VEVcc -Vcc CH2
+VECH2
-VEPre
-VcoSUB
GNDCH2
NFCH2
IN
STK402-090
STK402-090
1
15
