Protection - Sony KD-34XBR2 Training Manual

(FROM
SECONDARY
POWER
SUPPLY)
D8027
(Q5030/C
H OUT)
START
CONV.
IC8001
OP AMPS
NJM2901M
+
2 B
-
-
13 C
+
IC8001
OP AMPS
NJM2901M

Protection

There are two protection circuits for the HV stage. The first causes the HV to stop, leaving the TV' s audio to
continue operating. The second shuts off the entire TV set.
No or Momentary High Voltage
Excessive HV
A representative sample of this HV is available at the cathode of D8014. Since D8014 is difficult to access,
D8025/cathode is the same electrical point but easier to access. D8025/cathode' s normal voltage is 32Vdc when
the HV is 31.5kV.
This sample voltage from D8014 is applied to IC8001/B to stop the HV if it becomes excessive. IC8001 consists
of four op-amps in the same package, all with their negative inputs connected to a +5V reference voltage held by
zener D8004.
When the HV is excessive, the sample voltage input IC8001/pin 5 rises higher than the +5V reference voltage,
causing IC8001/pin 2' s output to go HIGH. The HIGH output is applied to inverter Q8004 that outputs a LOW.
This LOW output from Q8004 (collector) grounds IC8002/pin 1 and stops the HV oscillator IC8002.
Below Normal HV
After the TV is turned ON, if the HV drops lower than normal, the HV oscillator will stop. Below normal HV is
monitored by IC8001/A. In normal operation, a sample of the HV from D8014 causes 33V zener D8025 to
conduct. The HIGH that is output D8014 is turned into a LOW by inverter Q8010. Q8010' s LOW output is passed
D8003
+200V
Q8009
OCP
ON
AFC
PLS
+
Q8001
C8004
H PULSES
KEEP C8004
HV
DISCHARGED
0V
0V
5
5.1V
4
REF.
1
VOLT.
D8004/C
OP AMPS
NJM2901M
10
R8006
11 14
D8007
R8044
Q8008
ABL
FIGURE 9-2 - HA-3 CONVERTER BLOCK
SHUTDOWN LATCH
Q6530,Q6532
R8051
R8053-
R8055
V
OFF
SENSE
IC8002
1
HV DRIVER
Q8002
MCZ3001D
100
R8056
OFF
RV8002
HV
Q8004
EPOXY
OFF
COATED
Q8003
D8002 D8005
Q8007
7
+
A
-
6
+15V
R8016
IC8001
D8004
5.1V
8
-
D
+
9
R8021
R8144
R8042
TO CN5506 PIN 2
4.36 TO 4.66 VDC
33
9. High Voltage Power Supply
VD
18 VC1
8
CONVERTER
TRANSISTORS
FLYBACK
2
F/B
IC8003, IC8004
PH8001 ERROR
DYNAMIC FOCUS
DET
ABL
D8025
D8020
+
Q8010
C8005
47
R8078
RV8001
R8127
D BD.
HV TO
PICTURE
TUBE
FOCUS
VOLTAGE
(PICTURE
TUBE)
Q8022-3, Q8018
AMP
DF DRIVE
DQP CONTROL
IC5511/11
D8014
EPOXY
COATED
44tvp12 1358 9/4/01