Pioneer XV-EV61 Service Manual page 133

5
Protection circuit that activates against a DVD ERR error
6 The DVDM monitors the voltage of the main power supply by VDET signals.
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 V+12
47k
10k 0
4.7k
Q924
10k
V+12
V+6 V+5
15k
10k
Items to be detected by VDET
(1) When the power voltages inside the DVDM become abnormal, as shown in the table below
Status
In Normal mode
When an abnormality is generated.
(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.
5
6
VPR+8
47k
V+12
Q921
10k
Q923
Q922
470
Q925
Q926
UDZS4.7B
47k
Power Voltage
Q923
off
<1V (on)
VDVD+12
>15.5V off
−
<5.2V
VPR+8
−
>12.6V
−
V+6 <3V
−
<3.6V
V+5
−
>6.6V
−
<2.5V
V+3R3
−
>4.25V
6
7
B E
DVDM Assy
D922
V+3R3
470
D921
0.1
Operation
Q924 Q922 Q921 D921
off off off off
(on) (on) (off) off
off off off off
off off off off
on on on on
− − − −
off off off off
on on on on
− − − −
− − −
(on)
XV-EV61
7
8
IF/AF Assy
220
µcom
VDET
17
IC5501
PDC108A:EV61
1M
0.01
PDC109A:EV31
VDET voltage
D922 Q926 Q925
off off off Mid
on off off
off on on
−
on on
−
off off
−
on on
−
on on
−
off off
− − −
− − −
8
A
B
C
L
L
L
H
L
L
H
D
L
H
E
F
133