Pioneer XV-DV430 Service Manual page 112

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Protection circuit that activates against a DVD PRTECT error 3 7 63 1515 0
6 The DVDM monitors the voltage of the main power supply by VDET signals.
A
In Normal mode, the VDET signal is at the MID level (3.3 V). In the following conditions, the VDET signal level becomes L or H, and
the microcomputer is notified of this abnormality.
V+12 V+5
R927
47k
R929
R928
10k
4.7k
R930
10k
D924
B
V+6
D926
D927
D925
Items to be detected by VDET
(1) When the power voltages inside the DVDM become abnormal, as shown in the table below
C
Status
In Normal mode
TE
L 13942296513
When an abnormality is generat
D
(2) When the VDET signal to the microcomputer is interrupted because of defective soldering of the 30-pin connector or incomplete
insertion of FFC
→ The VDET level is lowered by the pull-down resistor (1 Mohms) on the side of the microcomputer.
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VPR+8
V+12
R923
47k
R925
0
Q923
Q924
R924
10k
Q922
D923
V+12
V+5
R933 Q925
15k
Q926
R934
R931
10k
47k
Power Voltage
<1V
VDVD+12
>15.5V
<5.2V
VPR+8
>12.6V
V+6 <3V
<3.6V
V+5
>6.6V
<2.5V
V+3R3
>4.25V
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B
DVDM Assy
V+12
Q921
D922
Through
TRADE2
POWER
V+3R3
R922
R921
470
470
8
D921 C921
UDZS4.7B
0.1
Operation
Q923 Q924 Q922 Q921
off off off off
Q Q
(on) (on) (on) (off)
3 6 7
off off off off
−
off off off
−
on on on
− − − −
−
off off off
−
on on on
− − − −
− − − −
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XV-DV430
3
4
2 9 9 4
8
F
CONTROL Assy
R5588
220
20
VDET
µcom
17
R5591
1M
C5580
IC5501
0.01
PDC104A
D921 D922 Q926 Q925
off off off off
off on off off
1 3 1 5 0 5 8 2 9
off off on on
−
off on on
−
on off off
− −
on on
−
off on on
−
on off off
− − − −
− − −
(on)
m
co
.
4
2 8
9 9
VDET voltage
Mid
L
9 4 2 8 9 9
L
L
H
L
L
H
L
H