Sony KP-46WT520 Service Manual page 9

Self-Diagnosis Function Operation
+B overcurrent (OCP)
Occurs when excessive current fl ows through R6812. The increase in voltage across Q6803 causes it to turn on which sends a high signal to the
micro.
+B overvoltage (OVP)
IC6801 detects +B OVP condition and turns on Q6802. This sends a high signal to the micro and also shuts down the AC relay.
V-STOP
Occurs when an absence of the vertical defl ection pulse is detected by pin 56 of IC452 (A Board). Power supply will shut down when waveform interval
exceeds 2 seconds.
White Balance Failure
If the RGB levels* do not balance within 2 seconds after the power is turned on, this error will be detected by IC452 (A Board). TV will stay on, but
there will be no picture.
*(Refers to the RGB levels of the AKB detection Ref pulse that detects 1K).
Low B OCP/OVP
Occurs when set 5V is out.
Also check for : + 135V line shorted
+ 135V line is going over 145V
Horizontal Defl ection Stopped
Occurs when either:
1) a +B overcurrent is detected (Q6803), or
2) IC452 (A Board) is damaged.
Self-Diagnosis Block Diagram
IC702
MAIN MICRO
STBY-LED
STR
48
STBY-LED
44
OCP
45 OVP
43 LOW B ERR
5V
KP-46WT520/51WS520/57WS520
A
CLKO 28
DATO 31
G
AC RLY 69
1
4
Q6102
Q451
D6803
Q452
A
IC303
2 1
3
A
IC452
Y/C JUNGLE
AKB
58 CRT
53 SCL
VPROT 56 VDY-
R5104
52
SDA
HPROT 57
R5125
RY6000
Q5018
P_SW(-)
2
3
1K-PROT2
+B OCP
D452
D6505
+BVOP
D453
KP-46WT520/51WS520/57WS520
R5105
BM
D
2 IC5007 14
IC6801
+B
1
R6812
+B
D
D6805
R6803
+B OCP
5V
Q6802
2
3
+B
9