Pioneer XV-EV1000, Руководство по обслуживанию

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XV-EV1000
128
1 2 3 4
1 2 3 4
C
D
F
A
B
E
4
When DC is generated at the output because of
a failure in the AMP system, etc.
5
When abnormally high temperature is detected
by the thermistor
R3605
(R3625)
(R3615)
27k
R3606
(R3626)
(R3616)
27k
R3638
10k
Front L ch
(SW, SL)
+5V
C3632
470/6.3
Q3637
Q111
2SC4081
R113
220
IC81
TA7805S
R112
1k
TH111
NCP18WF104J03RB
R111
1k
Q3638
Q3632
Q3633
B
C
E
+
XPROTECT
to
XPROTECT
POWER Assy
J
R108
27k
VD+5
VD+5
AMP Assy
I
AMP Assy
I
Front R ch
(C, SR)
• In Normal mode, both Q3637 and Q3638 are off.
(1) When positive (+) DC voltage is generated at the SP
terminal
When positive (+) DC voltage is generated at the L or R channel,
and VB of Q3637 becomes higher than that at the operation point,
Q3632 (E, C, B) is turned on, and the level of XPROTECT
becomes low.
→
The microcomputer detects the XPROTECT level and shuts
the power to the unit off.
(2) When negative (-) DC voltage was generated at the SP
terminal
Q3638 is turned on, and XPROTECT is activated.
5
-1 IC81 abnormal temperature detection circuit
A
The voltage at Point
A
becomes the divided voltage of TH111
and R111//R112 (combined resistance of parallel-connected
resistors R111 and R112.) In Normal mode, the resistance at
TH111 is much higher than R111//R112, and Q111 is off. (Note
that the resistance at TH111 becomes lower as the temperature
increases.) If the solder temperature at IC81 increases abnormally,
the temperature at TH111 (thermistor) mounted closest to the land
of IC81 increases accordingly, and the resistance at TH111
decreases.
When the temperature at TH111 reaches 90-110_C (varying
according to conditions,) the voltage at Point (A) becomes high
enough to turn Q111 on, and the level of the XPROTECT line
becomes low. The microcomputer detects the XPROTECT level
and shuts the power to the unit off.
to
SYSPOW
POWER Assy
Q83
RT1P241M
Q81
2SD1858X(QR)
R83
18
RY81
XSR3008
R84
18
D87
DAN217
R90
27k
VD+5