Sony BVM-D14H1E Maintenance Manual page 77

The H. pulse is voltage-divided, wave-shaped by IC2501
and its peripheral circuit, and is sent to IC507 pin-6, the B
board and the MA board.
Amplitude of the horizontal deflection current is detected
by T2503, Q2513 and their peripheral circuit. The detect-
ed amplitude is fed back to the PWM control circuit.
Multiple S-shape correction capacitors are prepared, and
are selected by Q2514, Q2515, Q2516, Q2517, Q2518 and
Q2519. The S-shape correction capacitors are switched at
the following three points of horizontal frequencies:
Horizontal frequency of 15 kHz, H. frequency in the range
of 27 to 33.75 kHz and H. frequency in the range of 37 to
45 kHz. The horizontal linearity correction coils are
switched by the relay RY2501 when the H. frequency of
15 kHz is input.
The H. centering circuit consists of IC2502, IC2504 and
Q2504. The H. center position is controlled by amplifying
the H. CENT. DC signal that is supplied from IC508 (D/A)
and by super-imposing the DC current to the horizontal
deflection current. As to the power supply for IC2504, the
secondary winding of T2501 (HOT) is used so that a
floating power supply is realized.
4. Vertical Output Circuit
The vertical output circuit consists of IC2503 and its
peripheral circuit.
The vertical output signal is generated by inputting the V.
drive signal that is output form IC507 pin-29, to IC2503
pin-1 where it is amplified. The V. center position is
controlled by inputting the V. DC signal that is supplied
from IC507 pin-28, to IC2503 pin-7. The vertical deflec-
tion amplitude and the vertical center position are con-
trolled by IC507.
The vertical feedback pulse is generated by wave-shaping
the V. flyback pulse with R2570, R2571 and D2520, and
by inputting it to IC507 pin-30.
5. High Voltage Output Circuit
The HV drive signal that is output from IC515 pin-23 is
sent to the high voltage output circuit consisting of Q506,
Q507, Q513 (HV. OUT) and their peripheral circuit where
the flyback pulse is generated by resonance. The flyback
pulse is not only supplied to T502 (FBT) but also rectified,
smoothed out by D520 and C578 so that the rectified high
voltage is supplied to the C board as the G2 voltage.
Amplitude of the high voltage is voltage-divided by the
high voltage resistors inside the FBT, and is output from
T502 pin-14. The detected output of the high voltage is
again voltage-divided by IC520, R1509, R1576 and R1577
so that it is sent to the PWM control signal as the high
voltage feedback voltage.
BVM-D14H1U/D14H5U/D14H1E/D14H5E/D14H1A/D14H5A
6. Dynamic Focus Output Circuit
The H. focus signal that is output from IC507 pin-17 is
amplified by the H. focus amplifier consisting of Q510,
Q511, Q512 and the peripheral circuit. The H. focus signal
then drives T501 (DFT) where it is amplified to about 500
V and is supplied to T502 pin-17. The H. focus signal
interferes with the white balance reference pulse inside the
CRT and produces an ill effect. In order to prevent
occurrence of the ill effect, the H. focus signal is of a
constant voltage is used during the vertical blanking period
instead of the H. parabola signal. This switching is
performed by IC516, IC524 and the peripheral circuit.
The V. focus signal that is output from IC507 pin-32 is
amplified by the V. focus amplifier consisting of Q517,
Q518 and the peripheral circuit. The V. focus signal is
amplified to about 200 V and is supplied to T502 pin-18.
7. H/V Blanking Circuit
The H/V blanking circuit consists of IC501, IC527, IC509
and the peripheral circuit. Timing of the H. blanking
signal is determined by the timing reference signal. The H.
SAW signal that is output from IC507 pin-16 is used as the
timing reference signal for the H. blanking. IC501 deter-
mines the start position of the H. blanking and IC509
determines the end position of the H. blanking.
The V. blanking circuit consists of IC502, IC528, IC510
and the peripheral circuit. The V. SAW signal that is
output from IC507 pin-29 is used as the timing reference
signal for the V. blanking. IC502 determines the start
position of the V. blanking and IC510 determines the end
position of the V. blanking.
Timing control of the H/V blanking signal is performed
using the control voltage that is output from IC512 (DA).
8. Protector Circuit
The H/V protector circuit consists of IC523, IC514 and the
peripheral circuit. When the voltage that appears at T502
pin-6 (FBT tertiary winding) exceeds the reference voltage
that is set by IC514, the internal protector circuit of IC507
is started up through D506. The operating point of the H/
V protector circuit is set at about 27 kV of the high voltage
output.
The ik protector circuit consists of IC517, IC523 and the
peripheral circuit. The ABL current value is detected by
R1521, R1522 and R1523. When the detected current
value exceeds the reference voltage that is set by IC517,
the internal protector circuit of IC507 is started up through
D507. The operating point of the ik protector circuit is set
at about 1500 µA of the ABL current.
6-3