Pioneer XV-DV333 Service Manual page 100

1
Protection circuit that activates against a DVD PRTECT error
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
R851
47K
R852
15K
R853
10K
GNDD
V+12
B
R823
V+SR5 V+5V
15K
2SA1576A(RS)
D861
R824
R822
10K
47K
D862
D852
GNDD
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
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.
E
F
100
1
2
V+5V VPR+8
V+12
R881
47K
R882
10K
R801
470
V+3R3
GNDD
Q821
R821
Q801
DTC124EUA
R821
10K
Power Voltage
<8.8V
VDVD+12
>15.5V
<5.2V
VPR+8
>12.6V
V+6R5 <3V
<3.6V
V+5
>6.6V
<2.5V
V+3R3
>4.25V
2
3
B
DVDM Assy
Through
TRADE2
NORMAL : 3.3V
<
ABNORMAL : 0.5VDD POWER
>
0.85VDD
R801
470
4
VDET
GNDD
Operation
Q881 Q851 Q821 Q801
off off off off
on on off on
off off on on
−
off on on
− −
on on
− −
on on
−
off on on
−
on off on
− − − −
− − − −
XV-DV333
3
4
F
CONTROL Assy
R5588
220
6
VDET
17
R5591
1M
C5580
0.01
<
L 2.5VDD
>
H 4.25VDD
VDET voltage
Mid 3.3V
L
L
L
L
L
L
L
L
H
4
µcom
IC5501
PDC122A