Panasonic E3 / E3D / Chassis Service Manual / Other ▷ View online
7
2.
Single ABL
Purpose :
In a normal TV the ABL operation detects the current
following to the secondary coil of the fly-back transformer
and controls the contrast. In a video projection TV,
however, the current for the secondary coil of the fly-back
transformer is measured as the total current for the three
projection tube. Therefore the current can not be controlled
even if most of the electron beams are sent though one
projection tube. For this reason the monochrome ABL
circuit detects the maximum current for each projection tube
and controls the same. We have added a circuit which
accelerates the ABL operation time, and lowers the
contrast.
In a normal TV the ABL operation detects the current
following to the secondary coil of the fly-back transformer
and controls the contrast. In a video projection TV,
however, the current for the secondary coil of the fly-back
transformer is measured as the total current for the three
projection tube. Therefore the current can not be controlled
even if most of the electron beams are sent though one
projection tube. For this reason the monochrome ABL
circuit detects the maximum current for each projection tube
and controls the same. We have added a circuit which
accelerates the ABL operation time, and lowers the
contrast.
Operation :
In normal ABL operation detects the current flowing to FBT
which supplies the high voltage to the three projection
tubes, as with a standard TV. This is alike MD2 chassis.
The current flowing to each projection tube is detected in
the colour output transistor emitter, and the maximum
current to each projection tube is then input to the Q7735
through D3352,D3362 and D3372.
In normal ABL operation detects the current flowing to FBT
which supplies the high voltage to the three projection
tubes, as with a standard TV. This is alike MD2 chassis.
The current flowing to each projection tube is detected in
the colour output transistor emitter, and the maximum
current to each projection tube is then input to the Q7735
through D3352,D3362 and D3372.
Then output value of Q7735 is input to pin No. 5,7,9 and 11
of IC7705, these are compared with pin No. 4,6,8 and 10 of
IC7705.
Compared result is output from pin No..1,2,13 and 14 as
P0, P1, P2 and P3. P0-P3 data are input to IC7702, then
CRT current following is separated to 5 levels/ Ranks in the
IC7702 as follows.
of IC7705, these are compared with pin No. 4,6,8 and 10 of
IC7705.
Compared result is output from pin No..1,2,13 and 14 as
P0, P1, P2 and P3. P0-P3 data are input to IC7702, then
CRT current following is separated to 5 levels/ Ranks in the
IC7702 as follows.
P0
P1
P2
P3
RANK
LEVEL
H
H
H
H
A
Danger
H
H
H
L
B
I
H
H
L
L
C
I
H
L
L
L
D
I
L
L
L
L
E
Safety
Detection data is input to MPU through IIC bus line and
MPU controls the contrast to keep detection level safety.
MPU controls the contrast to keep detection level safety.
R,G,B OUT
Q7735
D3352,D3362,D3372
CRT-Anode
FBT
T554
Q9601
4
5
7
6
8
9
11
10
2
1
13
14
+5v
IC7705
M5234P
M5234P
IC7702
CX1315P
CX1315P
10
9
2
1
14
15
59
60
IC1101
MPU
MPU
IC1309
Display Processor
Display Processor
43
11
10
BCL
SDA
SCL
+
-
+
-
+
-
+
-
E10 A10
16
1
P3
P2
P1
P0
LG1/W3
8
IIC bus
Q3351
Q3361
Q3371
AB
8
3.
Shading
Purpose :
To correct variations in the left and right shading due to
differences in the positions of the projection tubes, to
correct gamma and to blank the final sweep interval.
To correct variations in the left and right shading due to
differences in the positions of the projection tubes, to
correct gamma and to blank the final sweep interval.
Shading Correction :
Horizontal parabola wave is made by horizontal plus via
Q7741-Q7744 and Q7745-7747. H.SAW wave and
Horizontal parabola wave is made by horizontal plus via
Q7741-Q7744 and Q7745-7747. H.SAW wave and
H.PARA wave is input to Pin No. 2 and 5 of IC7704, then
they are mixed in the IC7704 and then it is output from pin
No. 7 o IC7704.
The correction wave-form output from IC7704 is input to
pins 10 and 8 of IC7703, the R and B gain is adjusted, and
then the left and right brightness are varied to correct any
lack of colour uniformity on the screen.
they are mixed in the IC7704 and then it is output from pin
No. 7 o IC7704.
The correction wave-form output from IC7704 is input to
pins 10 and 8 of IC7703, the R and B gain is adjusted, and
then the left and right brightness are varied to correct any
lack of colour uniformity on the screen.
4.
Prevention of projection tube burn-out
Purpose :
This feature operates to prevent burn-out from occurring in
the phosphor substance of the projection tube when the
picture is stopped for an extended period.
This feature operates to prevent burn-out from occurring in
the phosphor substance of the projection tube when the
picture is stopped for an extended period.
Operation :
Each time the power is turned off, the channel is changed,
or AV input switching is performed, the screen display
position is moved and rotated horizontally and vertically
approximately 3 mm in a clockwise direction.
The MPU sends a command to move the screen display
position horizontally and vertically, to IC1309, through the
I²C Bus, for an input from the button on the TV, or from the
remote control, to turn the power on or off, or change the
channel, or switch the AV input.
Each time the power is turned off, the channel is changed,
or AV input switching is performed, the screen display
position is moved and rotated horizontally and vertically
approximately 3 mm in a clockwise direction.
The MPU sends a command to move the screen display
position horizontally and vertically, to IC1309, through the
I²C Bus, for an input from the button on the TV, or from the
remote control, to turn the power on or off, or change the
channel, or switch the AV input.
A3
W2
7
IC7704
AN6142
AN6142
H.SAW
Q7741
|
Q7744
HP-BLK
H.PARA
Q7745
|
Q7747
ADJ.
2
Q7748
7
5
10
8
19
18
20
IC7703
PA0057A
PA0057A
R-gain
B-gain
TPW101
TPW117
6
TPW2
+12V
R-out
G-out
B-out
(H.V)
(H+1.V)
(H.V+1)
(H+1.V+1)
9
5.
Single colour mode
Operation :
During the service mode, each colour (R,G and B) can be
displayed in P-Conver mode by using ” key of remote
control.
Command data is sent to IC7707(DAC) from IC1101(MPU)
via IIC bus line.
Then the voltage is output from pin No.1, 2 and 9 of IC7707
as follows.
During the service mode, each colour (R,G and B) can be
displayed in P-Conver mode by using ” key of remote
control.
Command data is sent to IC7707(DAC) from IC1101(MPU)
via IIC bus line.
Then the voltage is output from pin No.1, 2 and 9 of IC7707
as follows.
IC7707 Pin No.
1
2
9
B
H
L
H
G
L
H
H
R
H
H
L
R+G+B
L
L
L
Above voltage are applied to Q7718, Q7717 and Q7715 as
blanking plus though Q7728-30.
blanking plus though Q7728-30.
6.
Fan control
E3D chassis is required cool fan to falling the temperature
of inside of unit.
of inside of unit.
Operation:
The temperature is detected by thermistor, then its result is
infromed to pin 11 of MPU.
When the temperature rises to 90 ºC (point A), from pin 48
of MPU outputs “H” voltage, and then FAN is rotated.
The temperature is detected by thermistor, then its result is
infromed to pin 11 of MPU.
When the temperature rises to 90 ºC (point A), from pin 48
of MPU outputs “H” voltage, and then FAN is rotated.
After that temperature falls to 80 ºC (point B), from pin 48
MPU outputs “L” voltage, and then FAN is stopped to rotate.
MPU outputs “L” voltage, and then FAN is stopped to rotate.
Protection:
During following conditions, Pin 7 of MPU receives “H”
voltage,then protection circuit is operated. Set goese to
stand-by mode.
a)A5/SG7 connector and SG8 connector are disconnected.
b)The FAN is deffective itself.
During following conditions, Pin 7 of MPU receives “H”
voltage,then protection circuit is operated. Set goese to
stand-by mode.
a)A5/SG7 connector and SG8 connector are disconnected.
b)The FAN is deffective itself.
IC1101
MPU
59
60
CLK DATA
16
1
2
B BLK
IC7707
DAC
9
G BLK
R BLK
14
15
+9V
+9V
Q7730
Q7729
Q7728
1
2
B
9
G
R
IC7703
RGB out
Q7718
Q7717
Q7715
CRT-B
CRT-G
CRT-R
70
Temperature
of inside of
unit
(ºC)
80
90
100
Off
Low
Point A
Point B
Off
Low
On
High
FAN condition
MPU pin 48
MPU pin 48
IC1101
MPU
FAN OUT
FAN IN
11
48
PROTECT
7
A47
1
1
SG8
3
FAN
PROTECT
FAN
A5 / SG7
6
4
90 ºC = 0.8 V
80 ºC = 1.1 V
80 ºC = 1.1 V
Thermistor
10
7.
Protection
Relay
Protect
A2/W1
7
Q7115 <R>
Q7117 <G>
Q7118 <B>
CRT STOP
Q1030(INV)
RL6701
Q6751
+22V Short
circuit
D7755
-12V Short
circuit
+12V Short
circuit
+22V Over
current
Q7543
Q7545
-22V over
current
210V Short
circuit D863
circuit D863
140 over
current R862
current R862
23V short
circuit D859
circuit D859
15V short
circuit D855
circuit D855
Q848
-22V Short
circuit
D7549
Q849
Q846
8V short
circuit D853
circuit D853
+8V(H) short
circuit D870
circuit D870
-15V short
circuit D850
circuit D850
D7577<A>
D7560<A>
D500<B>
D514<B>
D400<C>
D868<B>
D869<B>
D861<B>
Standby LED
D1004
<CP-Board>
EHT
D513
D513
V-
Break
IC451
Break
IC451
FB
T
T
FBT
Pin1
ABL
<F-Board>
X-ray
IC411
IC411
<D-board>
LED
Pin 7 of IC1101 input
Holddown
Holddown
à 1.354-2.308V
Shutdown
à 2.554-3.508
Abnormal
à 3.754-5.000V
Pin12 of IC1101 output
<A>
<B>
<C>
4sec
Q511
Q400
Q503
E8
4
12
27
7
D11
8
P11
4
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