Page 1
MX-G50
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.
When replacing them, be sure to use the parts of the same type and rating as specified by the manufacturer.
(Except the J and C version)
Page 2
MX-G50
1-3
Important for laser products
1.CLASS 1 LASER PRODUCT
2.DANGER : Invisible laser radiation when open and inter
lock failed or defeated. Avoid direct exposure to beam.
3.CAUTION : There are no serviceable parts inside the
Laser Unit. Do not disassemble the Laser Unit. Replace
the complete Laser Unit if it malfunctions.
4.CAUTION : The compact disc player uses invisible
laserradiation and is equipped with safety switches
whichprevent emission of radiation when the drawer is
open and the safety interlocks have failed or are de
feated. It is dangerous to defeat the safety switches.5.CAUTION : If safety switches malfunction, the laser is able
to function.
6.CAUTION : Use of controls, adjustments or performance of
procedures other than those specified herein may result in
hazardous radiation exposure.
Reproduction and position of labels
WARNING LABEL
! CAUTIONPlease use enough caution not to
see the beam directly or touch it
in case of an adjustment or operation
check.
CLASS 1
LASER PRODUCT
Page 23
MX-G50
1-24
1) Before the actual adjustment, clean the play/recording
head.
2) Measuring tape :
i) VT-703(or equivalent 10kHz AZIMUTH control)
3) The cassette deck is connections as shown in figure 1-7.
Notes
AZIMUTH 1
SPK OUT
(VTVM is
connected to
the scope) - Turn the control
screw to as shown
in Figure 1-6.
Max output
and same phase
(both channels) After
adjustment
secure it with
REGION
LOCK.Remark Standard
To Adjust Pre-Setup
Item
StepPre-Setup
Condition
AZIMUTH
1
2
SPK OUT
(VTVM is
connected to
the scope) - Turn the control
screw to as shown
in Figure 1-6.
Max output
and same phase
(both channels) After
adjustment
secure it with
REGION
LOCK.
7mV(mV) Turn JSR2L,JSR2R
to the right and leftRemark Standard
To Adjust
Pre-Setup Item
StepPre-Setup
Condition
Fig 1-8
After putting VT-703
into Deck B
1)Press FWD PLAY
button.
After putting AC-225
into Deck B
1)Press REC PLAY
button.
2)MAIN PCB JCW3,
connectted to VTVM
Recording
Bias
Voltage
To adjust plabyback level/REC
2. Adjust Deck B Play Level/REC BIAS
1. Adjust Deck A Play Level
0.5
ii) AC-225(or equivalent)
After putting VT-
703 into Deck A
- Press FWD
PLAY button.
Page 41
MX-G50
1-42
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
16 32
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
D16D1
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) : 2channel AF 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 1
15
STK402-090 (AIC2) : 2channel AF power amp.
STK402-040
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 1
15
STK402-040
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 1
15
STK402-090
Page 63
3-8
MX-G50
5
14
15
Cassette mechanism assembly and parts list
Block No. MM
M 4
88
2
12
12
4
5
11 3
13
6
7
8
1
10
8
9
7
6
1
Item Parts number Parts name Area A
Parts list(Cassette mechanism)
Q'ty Description
Block No. M4MM
1 AH81-00141A REC/PB HEAD 1
2 AH81-00422A MOTOR ASS'Y 1
3 AH81-00364A MAIN BELT 1 1
4 AH81-00365A MAIN BELT 2 1
5 AH81-00101A FR BELT 1
6 AH81-00102A SOLENOID 1
7 AH81-00282A SPRING 1
8 AH81-00366A PINCH R.ASS'Y 1
9 AH81-00284A E-HEAD 1
10 AH81-00367A MOTOR BRACKET 1
11 AH81-00286A SWICH 1
12 AH81-00287A PHOT SENSER 1
13 AH81-00288ACONNECTOR 1
14 AH81-00289A LEEF SW 1
15 AH81-00375A PCB 1
TC881CB
ADR2400-SHU2L
ADR2400-MAIN0.5
ADR2400-MAIN1.3
ADR2400-MODE
ADR2400-MXS00220 ADR2400-SENSOR
ADR2400-16P
ADR2400-1PCB ADR2400-FR34.7
ADR2400-1
S/PP/R(F)
TC2131F
ADR241SWBRKT 110 ADR2400-PINCH(F)
Note: Parts listed on the Parts List below can be supplied.
However, parts that are not listed below cannot be supplied
individually but only by purchasing the whole Cassette
Mechanism Assembly Unit. (When ordering, use the Parts No.
AH59-00102A for Cassette Mechanism Assembly Unit.)
