Yamaha GX-505 Service Manual page 43

A B
PRINTED CIRCUIT BOARD (Foil side)
1
Point e (Pin37 of IC8)
H : 20 µsec/div
V : 2V/div
DC range 1 : 1 probe
0V
Point r (Pin39 of IC8)
H : 50 µsec/div
V : 2V/div
2
DC range 1 : 1 probe
0V
Point t
CH1 : Collector of Q19
CH2 : Anode of D11
3
V : 2V/div (CH1) V : 2V/div (CH2)
H : 2 sec/div DC range 1 : 1 probe
(This waveform is not available by pushing the power
switch ON and OFF.)
CH 1
CH 2
With the POWER ON, Disconnect the power
d i s c o n n e c t t h e A / C cord from the AC
power cord. Reconnect outlet.
the A/C power cord and
the above waveforms will
4
start.
Semiconductor Location
Ref. No. Location Ref. No. Location
D3 C2 IC3 G2
D4 C3 IC5 G2
D5 C3 IC6 C3
D6 E4 IC7 F3
D7 F2 IC8 E3
D8 D3 IC9 G3
D10 E4 IC11 G4
5 D11 D3 IC21 F2
D12 D4
D20 G4
D21 F4
D22 F4
D23 F4
D24 E4
D25 E4
D26 E4
6
C
Ref. No. Location
Q1 C2
Q5 G2
Q6 F2
Q7 G2
Q8 D3
Q9 D3
Q10 D3
Q14 D4
Q15 F2
Q16 C3
Q18 D3
Q19 D3
Q20 G4
Q21 G4
Q22 F4
Q23 F4
Q24 F4
Q29 F2
Q30 F2
Q34 D4
Q35 D2
Q36 D2
D E
GX-505VCD INPUT P.C.B. (1)
t
50
F G
(Surface Mount Device)
8 5
7 1
8 1
1 4
8 14
9 16
8 5
1 4
4 1
5 8
e r
H
GX-505/GX-505VCD
51