-7-
IC Block Diagrams
IC501 < Vertical Output > LA78040/TDA9302H
Thermal
Protection
-
+
AMP
Pump
Up
1
INVER
TING
INPUT
2
Vcc
3
PUMP UP
OUT
4
GND
5
V
e
r.
OUTPUT
6
OUTPUT
ST
A
GE Vcc
7
NON INV
.
INPUT
Service Information
This TV set has a built-in power supply protection circuit.
It is provided to protect the TV set in case of a power supply circuit malfunctions. When something abnormality
occurs during TV reception, the TV set goes to the stand-by mode.
When an abnormality occurs during TV reception, it causes pin 27 of the CPU to go continually Low(less than
0.75V) for about one second. The CPU detects that this has occurred and outputs the signal from pin 31 to
switch off the power supply lines.
Releasing the protective circuit and restoring power supply
To release the protective circuit and restore power supply, turn the power to the TV set OFF and then ON again
via either the main power switch or the ON-OFF button on the remote control. This will work only if the power
supply trouble was temporary. If there is permanent trouble such as a damaged circuit, power cannot be
restored and the circuit will have to be repaired.
■
Protection Circuit
IC3701 < Audio Control / Surround > NJW1142MP
6
8
1
7
20
10
25
22
NJRC
ORIGINAL
SURROUND
&
SIMULATED
STEREO
IIC BUS
INTERFACE
AGC
BIAS
TONE
VOL 1
TONE
VOL 1
VOL 2
VOL 2
19
18
14
13
16
15
17
30
21
23
24
12
11
IN 1a
AGC
TONE Ha
TONE La
OUT a
CVa
CVb
CTH
CTL
CSR
SCL
SDA
V+
GND
VREF
OUT b
SR-FIL
TONE Hb
TONE Lb
5
MONa
-2dB
SEL
2
IN 2a
3
IN 3a
4
IN 4a
IN 1b
SEL
IN 2b
IN 3b
IN 4b
29
28
27
MONb
-2dB
26
9
+4.5 dB
LINEa
LINEb
+4.5 dB
Summary of Contents for CP21KX2
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