Deflection And High Voltage Circuit - Sony TRINITRON PVM-14L2 Service Manual

5-2. Deflection and High Voltage Circuit

1. Sync Signal Processing Circuit
The horizontal and vertical sync signals that are input from the G board CN1502 (pin-4/pin-12), are sent
to the defection signal processor IC1551 (pin-26/pin-28).
In IC1551, the horizontal drive waveform, dynamic focusing parabolic waveform, picture distortion
correcting parabolic waveform, vertical drive waveform and H/V blanking waveforms that are required
by the deflection circuit, are generated and output. Waveforms of these signals are directly control by the
microprocessor via I 2 C.
The horizontal free-run frequency is adjusted by 480/60i (15.734 kHz).
2. Horizontal Output Circuit
The horizontal drive signal that is output from IC1551 is amplified by the horizontal drive circuit consist-
ing of Q1505 and the peripheral circuit. It drives T1502 (HDT) and Q1506 (H OUT). The H pulse that is
generated by the resonance of C1520, C1521, DY H winding impedance and primary winding impedance
of T502 (FBT), is divided of its voltage and is shaped by Q1508 and the peripheral circuit. The H pulse is
supplied to IC1551 pin-14 and to the B board as the AFC pulse.
The picture distortion correct is performed by the diode modulation circuit consisting of D1508, D1509,
L1505 and Q512 (PIN OUT). The picture distortion correct is controlled by the parabolic waveform
supplied from IC1551 pin-9.
T502 (FBT) is driven by the H pulse generated by Q1506 in order to supply high tension voltage to CRT.
The high tension voltage is about 23 kV for 14-inch model and about 27 kV for 20-inch model.
3. Vertical Output Circuit
The vertical output circuit consists of IC1501 and the peripheral circuit
The V drive signal that is output from IC1551 pin-8 is sent to IC1501 pin-1 where the signal is amplified
to generate the vertical output signal. For the V center position adjustment, the V DC signal that is output
from the B board IC352 pin-5 is input to IC1501 pin-7 so that the V center position is adjusted. The V
amplitude adjustment and V center position adjustment are controlled by the B board IC352.
4. Focus Output Circuit (PVM-20L2 only)
The H focus signal that is output from IC1551 pin-13 is amplified by the H focus amplifier circuit
consisting of Q501, Q502, Q503 and the peripheral circuit. Then the H focus signal drives T501 (DFT).
The H focus signal that is amplified to about 500 V is supplied to T502 pin-17.
Since the H focus signal gives adverse effect inside CRT as it interferes with the white balance reference
pulse, the H parabolic signal is not used by a constant voltage is used for the period during the V retrace
period. Switching between the H parabolic signal and the constant voltage is performed by Q1504 and
C1507.
5. Protector Circuit
The HV protector circuit consists of IC502, IC503 and the peripheral circuit. When the voltage at T502
pin-6 (the third winding of FBT) increases and exceeds the reference voltage set by IC503, the power
protector (+B voltage shut-down) is activated via D516. The operating point of the protector circuit is
about 27 kV (14 inch) and about 30 kV (20 inch) when converted to the high tension voltage.
The Ik protector circuit consists of IC502, IC503 and the peripheral circuit. The ABL current is detected
by R526, R507 and R528. When the detected voltage increases and exceeds the reference voltage set by
IC503, the Ik protector circuit operates so that the power protector (+B voltage shut-down) is activated
via D514. The operating point of the protector circuit is set to about 1500 micro amperes when converted
to the ABL current.
5-3
PVM-14L2/20L2