Protection Circuit - Pioneer XV-DV333 Service Manual

5

7.3.2 PROTECTION CIRCUIT

If the TIMER LED on the front panel flashes, check the protection circuit.
Note: If the protection circuit activates, the unit will not recover for 60 seconds even if the AC power cord is disconnected then reconnected.
If you activate Service Test mode, the protection circuit becomes invalid, which makes diagnosis easy. (To activate Service Test mode,
while connecting STEST port (IC5501 Pin43) to "+5V", connect AC power cord.) (Refer to "7.1.6 SERVICE TEST MODE")
There are three types of operations for the protection circuit, which are indicated on the FL display when Service Test mode is entered:
PRTCT WNG: The unit was shut down because of an abnormality in the AMP system. (The PROTECT line operates at the MID level.)
PRTCT ERR: The unit was shut down because of a failure in the AMP system. (The PROTECT line operates at the LO level.)
DVD PRTECT: The unit was shut down because of a failure in the DVD system. (The VDET line operates at the HI or LO level.)
Conditions for the protect circuit operations
Voltage
HI level >3.55V
PROTECT MID level 1.8V - 3.5V
LO level <1.8V
HI level >4.25V
VDET MID level 3.3V
LO level <2.5V
The possible failures for each error message are as follows:
PRTCT WNG:
• The Speaker terminal became overloaded because of short-circuit. (See 1.)
PRTCT ERR:
• The main power supply became LO level because of short-circuit or disconnection of connectors. (See 2.)
• Disconnection of the FAN connector or interruption of rotation of the fan (See 3.)
• DC was generated at the output because of a failure in the AMP system, etc. (See 4.)
• Abnormal temperature was detected by the thermistor. (See 5.)
DVD PRTECT:
• An error was generated in the main power supply inside the DVDM. (See 6.)
Protection circuit that activates against a PRTCT WNG error
1 When the Speaker terminal becomes overloaded
J
R3601 R3607
1.8k 0.1
POWER Assy
A
B
Front L ch
Q3601
R3603
33k
D3601
GND FL
D3603
DAP202K
Q3639
In Normal mode, the speaker (6 ohms) is connected between the
FL and GND FL points. Because the voltage at Point A is higher
than that at Point B, Q3601 does not operate.
If the resistance between the FL and GND FL points becomes
1.83 ohms or less, Q3601 begins to operate, Q3639 is turned on,
Q3640 (E, C, and B)is turned on, and the level of XPROTECT
becomes MID.
→ The microcomputer detects the XPROTECT level and
shuts the power to the unit off.
5
6
Normal
The unit is shut down because of an abnormality.
The unit is shut down because of a failure.
The unit is shut down because of a failure.
Normal
The unit is shut down because of an abnormality.
D
6CH AMP Assy
VD+5
R108
27k
+5V to
XPROTECT
R3639 R5559
27k 270k
Q3640
E
C
B
TRADE2
+
C3633
Assy
E
10/50
6
7
Conditions
POWER Assy
VD+5
R9506
27k
Q3646
DTA124EUA
XV-DV333
7
8
FL display in Service Test mode
PRTCT WNG
PRTCT ERR
DVD PRTECT
DVD PRTECT
RY1
XSR3008
Q51
2SD1858X(QR)
R53
RS3
18
PAN217
R54
18
8
A
B
C
D
E
F
97