XV-EV61
134
1
2
3
4
1
2
3
4
C
D
F
A
B
E
• The base voltage at Q3631 is a voltage between Points
A
and
B
divided by R3633 and R3634. As this voltage is negative (-) in Normal
mode, Q3631 is off.
When the AC power cord is disconnected and there is no AC power input, the base voltage at Q3631 b0.6 V or more, and Q3631
is turned on. Then, the operations below follow.
(1) SP Relay
Q3632 (E2, C2, B2), Q3633, and Q3636 (E, C, B) are turned on, the line to activate the SP relay becomes low level, and the SP Relay is
turned off.
(2) HP MUTE
Q3635 is turned on, and the MUTE circuit for HP is turned on.
Other protection circuit
AC detection circuit
This is a protection circuit that prevents popping sounds in the Speaker and Headphones output when the AC power cord is connected or
disconnected.
SP-TERMINAL Assy
N
• The voltage at Point
A
is a DC voltage which has been generated by half-wave rectification on the minus side of the AC power.
• The voltage at Point
B
is approx. 5 V.
Q3633
Q3636
Q3632
Q3635
Q3631
D3636
D3634
R3634
2.7k
R3633
6.8k
D3635
DAN202K
R3641
10k
B
C
C2
B2
E2
E
+
RYF
to SP Relay Circuit
to SP Relay Circuit
to HP MUTE
V+5D
V+B
R3632
22k
R3631
22k
R3642
1k
RYR
ACB
B
A
D3631
MTZJ5.1A
D3633
D3622
C3631
2.2/50
R3635
3.3k
