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EN 90
9.
T2 - T3
Deflection T2-T3
Vbatt
Line transistor
OPEN
Fly-back caps
DISCHARGE
DMV1500M
7405
*
BU2520DX
140V
F418
0V
3416
0V
47R
*
F419
GND_HOR
6471
E/W
7406
D
27V
3425
G
82K
0V
S
3434
I
4V8
I499
2K2
I415
T0
Figure 9-4 Deflection T2 - T3
At T2 the deflection current is 0 Amp. The fly-back capacitor
(2412/2413/2414) is charged to approximately 1200 V and will
discharge now. As a result of this, the deflection current will
bend the electron beam to the left of the screen.
Circuit Descriptions, Abbreviation List, and IC Data Sheets
ES1E
1
5455
5
NC
9
2
7
4
HORIZONTAL
1
DEFLECTION
2
COIL
4
2
1
3
I473
4
4
1
1
3
3
2
2
GND_HOR
3473
T3
T1
T2
T
F_15040_050.eps
040405
T3 - T4
Deflection T3-T4
Vbatt
Diode
CONDUCTS
DMV1500M
7405
BU2520DX
140V
F418
0V
3416
0V
47R
*
F419
GND_HOR
6471
E/W
7406
D
27V
3425
G
82K
0V
S
3434
4V8
I
I499
2K2
I415
T0
Figure 9-5 Deflection T3 - T4
When the fly-back capacitor (2412/2413/2414) is discharged,
the current is at its maximum negative level. This maximum
negative current will then charge the fly-back capacitor (2412/
2413/2414) with a negative voltage. At this moment, fly-back
diode 6404 will start conducting. The voltage at Scap 2418
causes a linear current flow from T3 - T4. This causes a
deflection current which bends the electron beam back from
the left to the centre of the screen.
9.2.2
Standby and Start Up
In Standby mode, both +5V and Vbatt are not available in order
to meet the standby power saving requirement.
During the start-up phase, +5V is switched on by STANDBY via
7548/7547/7545 and Vbatt is switched on by STANDBY via
7573.
After this, Hdrive is output from the SSB to driver 7404 (see
circuit diagram A2), and consequently to the deflection output
stage (7405). During the slow start-up phase, the Hdrive duty
cycle gradually increases from small to normal. At the
5455
5
1
NC
9
2
7
4
HORIZONTAL
1
DEFLECTION
COIL
2
4
2
1
3
*
I473
4
4
1
1
3
3
2
2
GND_HOR
3473
T4
T3
T1
T2
F_15040_049.eps
T
040405
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