Pioneer XV-DV434 Service Manual page 101

5
QQ
3 7 63 1515 0
Other protection circuit
AC detection circuit
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.
RYF
RYR
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.
• 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
TE
L 13942296513
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.
(2) HP MUTE
Q3635 is turned on, and the MUTE circuit for HP is turned on.
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POWER Assy
VD+5
D3635
VH+
DAN202K
R3631 R3632
R3633
33k 33k
D3634
10k
B
D3631
MTZJ5.1A
+
C3631
R3635
2.2/50
3.3k
D3632 D3633
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6
8
R3641
R3642
Q3632
E2
Q3631
B2
C2
R3634
4.7k
Q3635
A
D3636
Q Q
3 6 7 1 3
u163
.
XV-DV333
6
7
2 9 9 4 2 8
10k
to SP Relay Circuit
1k
to SP Relay Circuit
Q3636
C
B Q3633
E
to HP MUTE
1 5 0 5 8 2 9 9 4
m
co
7
8
9 9
A
B
C
2 8 9 9
D
E
F
101
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