Circuit Board Layout; Block Diagram - Yamaha F-20B Service Manual

F-20B

CIRCUIT BOARD LAYOUT

Top View
Front View

BLOCK DIAGRAM

MAIN 1/2
INPUT
JK1
POWER SWITCH
T1
SW1
T2
U, C, S, BS
4
MAIN 2/2
MAIN 1/2
GAIN SELECT
ACTIVE CH.
PASSIVE CH.
SW2
+12V
8
3 1
IC1
VR5
4
-12V
OP AMP
FUSE
FZ1
CN2 4P
T1
G
T2
POWER TRANSFORMER
AC Cord
MAIN 1/2
+12V
8
ACTIVE TYPE 2 1 5 7
IC3 IC3
TONE CONTROL
4
IC1,IC2
VOLUME
OP AMP
-12V
VR1
VR4 VR3 VR2
POWER SUPPLY CIRCUIT
GND
Side View
Power Transformer
MAIN 2/2
MAIN 1/2
JK3
MAIN 2/2
+B
5
1 4
IC4
POWER
3
AMP
-B
+B
+12V
JK2
-12V
-B
T3
T4
AUX IN
PHONE
4Ω Speaker