Pioneer XV-EV1000 Service Manual page 130

1
Other protection circuit
AC detection circuit
A
7 This is a protection circuit that prevents popping sounds in the Speaker and Headphones output when the AC power cord is connected or
disconnected.
J
POWER Assy
RYF
RYR
B
ACB
• 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.
C
• The voltage at Point B is approx. 5 V.
• 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 becomes +0.6 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 power amp mute becomes low level, and the power
amp mute is turned on.
D
(2) HP MUTE
Q3635 is turned on, and the MUTE circuit for HP is turned on.
E
F
130
1
2
VD+5
D3635
VH+
DAN202K
R3631 R3632
R3633 Q3631
22k 22k
10k D3634
B
D3631
R3634
MTZJ5.1A
2.7k
C3631 +
R3635
2.2/100
3.3k
A
D3632 D3633
XV-EV1000
2
3
R3641
STBY
R3642
STBY
Q3632
E2
Q3636
B2
C2
B
Q3635
D3636
3
4
to SP Relay Circuit
to SP Relay Circuit
C
Q3633
E
to HP MUTE
4