Pioneer XV-DV434 Service Manual page 98

1
QQ
3 7 63 1515 0
Protection circuit that activates against a PRTCT ERR error
A
2 When the main power supply becomes LO level
because of short-circuit or disconnection of
connectors
2 -1 Short-circuit-detection circuit for the amplifier
power circuit (VH+[VP+15], VD+5, -12 V [VA-12])
Circuit for shutting the power off when VP+15, VD+5, or VA-12
is short-circuited to ground (GND)
D
6CH AMP Assy
VD+5
Q101_1/2
(Q103_1/2)
B
R108
R101
27k
to
(R104)
XPROTECT
C
(µ-com) B
Q102_1/2
(Q104_1/2)
+
E
* ( )means the wiring No. of VP+15 line.
• In Normal mode, as Q101 (Q103) (E2, B2, C2) and Q102
(Q104) (E2, B2, C2) are on, the voltage at Point A is about 5 V.
The voltage at Point B is therefore about the same. As Q101
(Q103) (E, C, B) is off, Q102 (Q104) (E, C, B) is also off.
C
(1) When VH+(VP+15) is short-circuited to GND
As the voltage at Point B becomes almost ground potential, and
Q101 (Q103) (E, C, B) then Q102 (Q104) (E, C, B) are turned on,
the level of XPROTECT becomes low.
→ The microcomputer detects the XPROTECT level and shuts
TE
L 13942296513
the power to the unit off.
(2) When VH-(VA-12) is short-circuited
As the electric potential of VE at Q102 (Q104) (E2, C2, B2)
becomes the same as that at VB, Q102 (Q104) (E2, C2, B2) is
turned off. Following this, Q101 (Q103) (E2, B2, C2) is turned
off, which changes the voltage at Points A and B to a value other
D
than 5 V. Therefore, Q101 (Q103) (E, C, B) then Q102 (Q104) (E,
C, B) are turned on, the level of XPROTECT becomes low.
(3) When VD+5 is short-circuited
The level of the XPROTECT line becomes low. The
microcomputer detects the XPROTECT level and shuts the power
to the unit off.
2 -2 Short-circuit-detection circuit for the DVD power
supply (VP+8)
D
6CH AMP Assy
E
XPROTECT
TUNER
www
As the TUNER line is fixed to GND level, Q107 is always on. If
the level at VP+8 falls to GND level because of short-circuit, etc.,
Q106 is turned on, and the level of the XPROTECT line becomes
low.
← The microcomputer detects the XPROTECT level and shuts
F
the power to the unit off.
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2
VH+
(VP+15)
VD+5
Q101_2/2
(Q103_2/2)
E2
D101
E
(D102) Q102_2/2
B2
(Q104_2/2)
B
B
C2
C
C2
R102
(R105)
E2
1k
10k
R109
R103
A 820
C101
(R106)
(C102) D105
10k
1/50 (D106)
VH–
(VA–12)
VD+5 VP+8
R108
D104
27k 1SS355
Q106
DTC124EUA
Q107
DTA124EUA
x ao
y
. i
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3
8
2 -3 Short-circuit-detection circuit for VFDP
D
6CH AMP Assy
VD+5
to
XPROTECT
(µ-com)
Q115
DTA124EUA
B2
If VFDP is short-circuited to GND, or if the DC electric potential
at FL AC1 becomes GND level (in Normal mode: about -27 V)
because of a failure in the DC bias circuit of FL AC1, Q114 then
Q115 are turned on, and the level of XPROTECT becomes low.
→ The microcomputer detects the XPROTECT level and shuts
the power to the unit off.
Q Q
3 When the FAN connector is disconnected or
3 6 7
when rotation of the fan is interrupted
D
6CH AMP Assy
VD+5
R108
27k
to
XPROTECT
(µ-com)
C2
Q3651_2/2
RN1901
E2
If no fan is connected between FAN+ and FAN-, or when the fan
cannot rotate because of a foreign object caught in the blades, the
BASE of Q3652 becomes OPEN, and Q3652 and Q3651-
B) are turned off. Then Q3651-
the level of XPROTECT becomes low.
→ The microcomputer detects the XPROTECT level and shuts
the power to the unit off.
When FAN+ and FAN- are short-circuited, the electric potential at
Point A becomes higher than GND level by the addition of the
u163
values at D3656 and D3657. As this value is lower than that at
D3658, Q3651 (E, C, B) is turned off, Q3651 (E2, B2, C2) is
turned on, and the level of XPROTECT becomes low.
XV-DV333
3
4
2 9 9 4
E
TRADE2 Assy
R108
27k
R114
R112
1k
Q114
2SD2114K
R113
(VW)
220k
VA-12
1 3 1 5 0 5 8 2 9
VPF+15
R3654
1.8k
A
D3658
Q3652
UDZS3.9B
DTA124TK
C
B2
B
R3658
+
33(1/4W)
2.2k
E
D3657
C3652
Q3651_1/2
47/50 1SS355
RN1901
1SS133
Q3654
R3655 2SD2144S
8.2k
R3656
22k
V-12F
(E2, B2, C2) is turned on, and
2/2
m
co
.
4
2 8
9 9
82k
FL AC2
9 4 2 8 9 9
R3657
FAN+
D3655
FAN–
D3651
1SS133
(E, C,
1/2