Pioneer VSX-C501-S, Руководство по обслуживанию

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VSX-C501-S
89
5 6 7 8
5 6
7
8
C
D
F
A
B
E
7.1.4 Circuit Description
to XPROTECT
µ
-com
AMP Assy
R108
27k
R101
(R104)
1k
C101
(C102)
1/50
Q102
(Q104)
Q101
(Q103)
D101
(D102)
D105
(D106)
UDZS7.5B
Q101
(Q103)
C2
E2
B2
E2
C2
B2
C
E
B
E
C
B
Q102
(Q104)
R102
(R105)
10k
R103
(R106)
10k
A
B
VD+5
VD+5
VH+
(VP+15)
VH–
(VA–12)
• 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.
(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 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 than
5 V. Therefore, 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 the
power to the unit off.
(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.
1
Short-circuit-detection circuit for the amplifier
power circuit (+15 V[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)
XPROTECT
µ
-com
Q3654
2SD2144S
(VW)
Q3652
DTA124TK
Q3651
RN1901
Q3651
RN1901
D3658
UDZS7.5B
D3657
1SS355
FAN+
FAN-
C2
E2
C
E
B
B2
D3656
S5688G
D3655
1SS133
V+12F
VD+5
R3656
22k
R3655
8.2k
R108
27k
R3654
1.8k
R3658
2.2k
R3657
33(1/4W)FU
C3652
47/50
AMP Assy
V-12F
A
2
FAN Detection Circuit
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 (E, C, B)
are turned off. Then Q3651 (E2, B2, C2) is turned on, and 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
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.
Note: Refer to the Schematic Diagram about the actual circuit.
(The
&
number corresponds to the marked circuits.)