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1
QQ
3 FAN detection circuit
3 7 63 1515 0
C
6CH AMP Assy
A
VD+5
R108
27k
to
XPROTECT
(µ-com)
C2
C
B2
Q3651_2/2
RN1901
E2
E
Q3651_1/2
RN1901
B
If no fan is connected between FAN+ and FAN-, or when the fan
cannot rotate because of a foreign object caught in the blades,
current will not flow to R3657, 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
C
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.
TE
L 13942296513
4 DC detection circuit of SP terminal
R3357
(R3457)
D
18k
Front L ch
(SW, SL)
Front R ch
(C, SR)
R3358
+
R3603
(R3458)
10k
18k
• In Normal mode, both Q3605 and Q3604 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,
E
and VB of Q3605 becomes higher than that at the operation point,
Q3606 (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
www
Q3604 is turned on, and XPROTECT is activated.
F
40
1
http://www.xiaoyu163.com
2
VPF+15
R3654
1.8k
A
D3658
Q3652
UDZS7.5B
DTA124TK
B
R3658
R3657
+
33(1/4W)
2.2k
D3657
C3652
47/50
1SS355
D3655
1SS133
Q3654
R3655
2SD2144S
8.2k
D3651-D3654
R3656
22k
V-12F
1/2
(E2, B2, C2) is turned on, and
2/2
6CH AMP
D
C
POWER Assy
Assy
VD+5
+5V
R108
Q3606
27k
E
B
XPROTECT
C
Q3605
C3602
Q3607
Q3604
100/10
x
ao
.
i
2
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3
5 IC81 abnormal temperature detection circuit
IC81
NJM7805FA
FAN+
The voltage at Point A becomes the divided voltage of TH111
and R111//R112 (combined resistance of parallel-connected
FAN–
resistors R111 and R112.) In Normal mode, the resistance at
TH111 is much higher than R111//R112, and Q111 is off. (Note
1SS133×4
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.
(E, C,
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.
Q Q
3
6 7
u163
y
S-DV830
3
2 9
9 4
8
VD+5
6CH AMP
C
Assy
TH111
NCP18WF104J03RB
to
XPROTECT
A
R113
220
Q111
2SC4081
R111
R112
1k
1k
1 3
1 5
0 5
8
2 9
m
co
.
4
2 8
9 9
9 4
2 8
9 9
4