Casio MG-500 Troubleshooting guide

Service
Manuau
&
PARTS
LIST
cme
MIDI
GUITAR
MG-500
MG-510
AUG.1987

CONTENTS
1 SCHEMATIC DIAGRAM...
1-1 PCBs M385-MA1M, CN1, CN2.
1-2. PCB M4385-MA2M..
2 PCB VIEW...
2-1 PCB M385-MA1M
2-2 PCB M385-MA2M
2:3 PART NUMBER REFERENCE TABLE.
2-4 PCB M385-MA1IM
2-5 PCB M385-MA2M.
3.
CIRCUIT
DESCRIPTION.
3-1
WIRING
DIAGRAM.
3-2
BLOCK
DIAGRAM.
3-3
CIRCUIT
BLOCK.
4 CPU (uPD78C10G) PIN FUNCTION:
5 GATE ARRAY F.
6
INTERNAL
CIRCUIT
OF
GATE
ARRAY
(1)
Frequency
Detection
Counte
(2)
Peak
Detection
Circuit.
(3)
Address
Latch
(4)
MIDI
Buffer.
7 “MIDI CIRCUIT.
8 RESET CIRCUIT.
9
RELATION
BETWEEN
FRET
PITCH
&
FREQUENCY,
10 TEST MODE
11 ADJUSTMENTS..
PARTS LIST
EXPLODED VIEW..
OPERATIONS.
MIDI Implementation Chart.

1.
SCHEMATIC
DIAGRAM
=e
Ha
CY
a
a
Sa
na
ae
ae
ea

2
PCB
VIEW

2-4 PCB _M385:MAIM
2.3
PART
NUMBER
REFERENCE
TABLE
Resistors.
[im
47k
R25~R30
1K2Q
R41,
R42
Ez
1m
Z|
R2
1K2
‘R31
1KQ
R43VRA6
Not
used
R3VRS
Not
used
R32
1K2
R47
R59
Not
used
[
Revaie
|
47K2
R33
2200
REO
a0
R19
1ko
~
|
Rs
1K
Ret
10Ka
R20
47KQ
R35
10KQ
|
R62
1KQ
|
R21
1KQ
R36,
R37
Ka
R63
wkKaQ
naz
|
a7Ko
R38
2200
roa
22k2
R23
1Ka
i)
1Ka
Ros
10Ka
R24
4a7Ko
R40
10KaQ
[res
ia
Sts and tC
=
7
cr
uPD78610G-1B-X}
C3
wPD65031GC169
|
ICS
NJM78LO5R:
(GAF)
102
uPo2sc256eG-
|
Ic
pstsi8a2
|
108
HPD74HCUOSG
Capacitors
aI
3
=
see
|
crs
|
2200F
c19
330
pF
31
25V4.u
a
revi0#
aI
20
220
pF
cx2—|
_330pF
cy
oomr
ca
_-30pF
33
15
pF
(Non
polarity)
cexctt
|
2200F
cz
Tevi0#
caavcas
|
220
0F
12
16V10n
C23
0.01
pF
|
cas
15pF
(Non
polarity)
13,c14
|
220pF
c2a
|
220
pF
a7
0.01
uF
oo
330
pF
c25<027
|
330
pF
cas
tova34
cié
220
pF
28
0.01
uF
C49,
C50
56
pF
(Non
polarity)
7
30pF
|
C28
16VI0%
cst
0.01
uF
[e
8
220
pF
30
16v22n
52
100
pF

Oscillators
x1
NRastomie
|
x2
NR-18-2MHz
coit
u
$8c-03
Zener Diodes
z01
HzMsc
1,02
|
1ss220-1

2-6 PCB _M385.MA2M
Resistors
+
RIVR3
47kKQ
R36
47K2
R71
22K
‘Re
2KQ
R37R38
47KQ
R72VR73
47KQ
RS
22K2
R39VR40
100
KQ
R74
47m
RE
1KQ
Rat
22mMQ
R75
1KQ
a7
47KQ
Raz
2KQ
|
R76
100
K2
RB
22M2
[Raa
47KQ
a7
22K2
RO
27M2
R44
10KQ
R78
27MQ
RIOVRI2
100
KQ.
R45.
R46
100
KQ
R79
22M2
R13
330K2.
Ra?
WOKa
|
Reo
1ka
Rw
22K
R48.
RAD
100
KQ.
‘Ret
100
K2Q
RIGVAI?
47
KQ
R60
sa
Re2
22Ka
RIB
2KQ
‘RST
3BoKnQ
R83
27M2
[Care
toKa
Rs2
22Ka
Res
22a
R20vR21
100K
RSSAAS4
47K
Res
222
R22
47Ka
R55
2K2
|
Res
330K2
[
R23.
R24
100
KQ.
RSE
47KQ
R87-R88
100K2
R26
330
KQ
R57
1K2
R89
47KQ
R26
222
nse
22K
R90
2K
R27
22M
R59
100
Ka
ROIWRO2
47K
R28
27M
60
27M
R93
47K
R29
22kQ
R61
47kQ
RO4VRO7
100
K2
30
100
K@
Rez
22Ma
R98
10Ka
Rat
1Ka
~
[res
22k2
ROOWR100__100
K2
R32
27
M0
Res
3302
R101
10Ka
R33
22k
RESVRES
100K
R102
22k2
R34
1Ka
|
Reo
10K
R103
330K2
cr
100
Ka
R70
aKa

Capacitors:
ce
0.012
uF
oz
0.033
uF
as
4700
pF
CI
0.047
uF
Cy
1000
pF
ca
8200
oF
Cy
8200
pF
ce
|
(0.022uF
as
0.087
uF
CI
001uF
25
Cora
C46
0027
uF
cs
1000
pF
26
0.033uF
car
0.022
yF
cs
O01yr
27
0Viu
8
1000
pF
7
3300pF
=|
C28
O0tur
co
|
(ome
ce
16800
pF
29
0.018
F
C50
0.033,
F
o
Sov
wer
30
OomF
cst
0.0474F
C10
oor
cst
0.027
uF
cs2
Sov
war
ci
018
F
x2
or
F
53
6800
pF
12
1000
pF
33
sovipeP
54
0.0181
F
13
O.018
uF
34
tovaa
55
01m
F
cia
0.087
uF
035
0015
uF
56
O01
nF
cis
ooue
36
0.047
uF
cs?
0.087
uF
ci6
OomF
7
O012uF
ose
1000
pF
7
5600
pF
38
0015
uF
59
0.087,
F
cre
S0V1)8P
oe
1000
pF
260
00m
F
cre
0.018
uF
co
0001
uF
co
00271
F
20
0.087
uF
Co
O01uF
062
00121
F
21
sovIH
az
Sov
wer
|
83
sovuaP
Diodes

3-1
WIRING
DIAGRAM
M385—CNI
(Console)
3
CIRCUIT
DESCRIPTION
M385-MA2M
(Linear circuits)
MAIN VR@)
M385—CN2
BATTERY
BOX
AAx6
(Jock panel)