Yamaha R-S300 Service Manual page 50

A B
R-S300
1
MAIN (1) P.C.B.
(Side A)
2
3
4
• Semiconductor Location
Ref no. Location
D101 D4
D103 D6
D105 E3
D106 F3
D117 H6
D118 H6
D119 H6
5
IC101 E2
Q101 C4 OPERATION (2)
(W803)
Q102 D5
Q103 D4
Q104 D5
Q105 D4
Q106 D5
Q107 C4
Q108 D6
Q109 E3
6
Q110 F3
Q111 E4
Q112 E4
Q113 F4
Q114 G4
Q115A E3
Q116C D3
Q117C F3
Q118A G3
7
50
C D
MAIN (2) P.C.B.
CB107
Note) Those parts marked with "#" are not included in the P.C.B. ass'y.
#
Q115A
CB101
W105
OPERATION (6)
(CB706)
E F G
Notes)
Safety measures
• Some internal parts in this product contain high voltages and are dangerous. Be sure to take safety measures during servicing, such
as wearing insulating gloves.
• Note that the capacitors indicated below are dangerous even after the power is turned off because an electric charge remains and a
high voltage continues to exist there. Before starting any repair work, connect a discharging resistor (5 k-ohms/10 W) to the terminals
of each capacitor indicated below to discharge electricity. The time required for discharging is about 30 seconds per each.
C135, C136 on MAIN (1) P.C.B.
(Side A)
PREMT
SWMT
MG
+5S
PWR_MGT
FUNCTION (1)
THMR
THML
(CB506)
SPBRY
SPARY
IC101
HPRY
PRI
PRO
# # #
Q115C Q117A Q117C
5 k-ohms 5 k-ohms
10 W 10 W
OPERATION (13)
H I
OPERATION (2)
(CB805)
W104
W103
CB105
POWER TRANSFORMER
(CB26)
J
A, G, L models