Protection Circuits - Sony KD-34XBR2 Training Manual
Direct view & projection tvs
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Chart 20-1 summarizes the TV' s seven protected areas. Use Chart 20-1 and Figures 20-2 and 20-3 to verify the
signal that triggered the protection (shutdown). If no signal triggered the protection, suspect Micro IC001 on the
B board and the latch transistors (Q6105/Q6119) on the G board of causing the TV shutdown.
Chart 20-1 - Shutdown Causes
Stby
Protected Area
LED
Circuit
Blinks
0 X
+AC line OVP,
15V OVP, 22V
OCP
2 X
+135V OCP
3 X
+135V OVP
4 X
V Out
Loss
5 X (pix
IK balance
blanked
-TV
remains
ON)
6X
Q6.5V OVP &
OCP
7X
H Out Drive
Protection Circuits
After the TV enters a protective state, the standby light blinks to identify one of seven problem sections. The
problem section not only consists of the protected circuit (load), but also the sensing circuit that monitors the fault.
In the following seven sections, there is a description of the sensing circuit itself so you know how the load is being
protected and a test procedure to determine if the board that contains the load or circuit is at fault.
Standby light blinks 0 times – TV Shutdown
Refer to Figure 20-4 for the Circuit description and the Testing procedure that follows.
Circuit – When the TV shuts down (no line current) and the Standby light does not blink (indicates the trouble
area), three protection circuits are suspect:
•
AC Input OVP
•
+15Vdc OVP
•
+19Vdc OCP
•
+22Vdc OCP
The first two areas are most likely confined to the G board. The 19Vdc and 22Vdc OCP is likely to be a D board
problem.
Shutdown
Verification
Bd
Location
Normal
Voltage
G,
G Bd -
0.1Vdc
D
PH6004/
pin 3
D
CN6101/
0.1V
pin 6
D
CN6101/
0.1V
pin 7
D,
D Bd -
5Vp-p
A
CN8004/
Pulses
pin 7
at V rate
C/A
A Bd –
3 pulses
/G2
CN3011/
in
adj
pin 9 or
vertical
CR Bd
interval.
CN3703/2
Q
G Bd -
0.1Vdc
box
CN6101/
, G
pin 8
D,
D Bd -
H pulses
A
CN8006/
5Vp-p
pin 6
20. RA-5A Chassis Protection Block
CN6104
2
PH6004
1
FIGURE 20-2
CN8022
FBT
FIGURE 20-3
86
CN6102
CN6101
4
3
PRIM
STANDBY
P.S
P.S
D6015
-
+
AC IN
HOT
GND
T.P.
CN8003
CN8013
H OUT
CN8016
V OUT
CONV. IC
CN6106
SEC
P.S
RA-5A
G BD.
CN3005
CN3006
CN3002
CN3008
RA-5A
D BD.
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