High Voltage Production; Horizontal- Offset Deflector - Loewe Q2500B Serviceanleitung

Technology of Q 2500 colour TV set

2.4.1 High voltage production

Q2500 secondary H output stage
Pin10
C532
100p/500V
R550
2k2
R542
1k8/2%
D531
T531
RU2M
12
32kV
16
R548
R531
120R
3R3
FOCUS
13
5
R534
MP20
3R3
FOCUS
1
UG2
7
10
4
8
6
9
3
2
The high voltage transducer also contains the
cascade. The secondary winding of the step
up transformer is divided into four and the
high voltage rectifier diodes are connected
between the individual winding sections. This
form of high voltage production is possible
without the highly charged capacitors used up
to now, which increases the reliability of high
voltage production and makes possible a
space-saving compact solution.
The resistance voltage divider and the poten-
tiometer of the focus and G2 adjustment is
integrated mechanically into the splitting com-
bination for units with 4:3 c.r.t.s.
The filament voltage of the c.r.t. is assigned to
pin 9. On pin 4 the flyback pulse for the syn-
Document Q 2500
W511
Pin11
R545
C511
R551
22u/250V
150k/2%
C549
R552
UVideo
D549
1M
22n UF
C30V
D548 B560
D547
1N4148
R5
BA159
USVM
R547
C547
3R3
L553
100p/500V
D558
UV-
R558
RU2M
1R
C556
100p/500V
C558
2200u
D557
UV+
R557
RU2M
1R
C557
100p/500V
chronisation of the control is assigned to pin 4.
At the same time this pulse is rectified by
D547 and fed to the c.r.t. plate via connector
W 549. The 60V occurring here is required by
the c.r.t. PCB for the speed modulator. The
UV+ and UV- for the vertical stage (approx. +
13 V) occur in the windings between pin 6 and
9 and pin 3 and 9.
Just like the amplitude of the radiation current
a corrective voltage for the stabilisation of the
horizontal amplitude can be tapped at the
base, connection 10 of the high voltage wind-
ing.
This radiation current dependent voltage is led
to the signal board via pin 11 of connector
W 511. The radiation current fuse and limiter
are found here.
The operating voltage U 200 for the video
output stage is tapped on the primary side of
W550
the pin 5 of the diode split transformer and
5
rectified by D 531. In addition on connection 5
4
3
another voltage UB -10 V and on pin 7 a volt-
2
age of UB +10 V are produced, which are felt
1
on capacitors C 535 and C 534. On UB = 136
V there are 126 V and 146 V. These voltages
are required for the offset correction of the
horizontal deflector.

2.4.2 Horizontal- offset deflector

The deflector pulse is formed in such a way
that through the deflection and S-correction a
linear deflection results. This only functions
however when the deflection is exactly cen-
tral. As the Q 2500 chassis could also be used
as a VGA monitor, high demands are placed
on linearity. For this reason the possibility of
offset correction is created.
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