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87
2. SIDE DPC
2-1. Outline
Since the deflection coil used in 29 and 34" type of N5SS
chassis is not a DPC free type left and right pin-cushion
distortion must be corrected with a circuit.
If the distortion is not corrected, pin-cushion distortion as
shown in Fig. 12-2 (a) will occur.
To correct this distortion, a H deflection current must be
modulated in a form of parabola for V sync period.
The compensation circuit using a diode modulator system
which has a large amount of compensation ability is used in
N4SS chassis.
The correction circuit in N5SS chassis is of a negative type
and the diode modulator develops a negative voltage.
Accordingly, a negative power supply is used in the amplifier
and the output circuit.
The circuit can be controlled through the I2C bus. That is, the
parabola waveform and DC voltage obtained by controlling
E/W output (pin 2) of Q302 (TA8859P) through the bus is
shifted in their levels by zener diodes (D464, D465, D466)
to use them as a negative power source. The voltage is added
to the amplifier and the output circuit (Q462, Q460) and
modulates the voltage at CD11 in the diode modulator
circuit. Thus developed parabola voltage is a negative voltage
and the sum with the main B voltage (VB) is applied across
the S character capacitor. This voltage works as a power
supply for the H deflection yoke and the H deflection current
is modulated as shown in Fig. 12-2 (b), thus correcting the
left and right pin-cushion distortion.
Fig. 12-3 Diode modulator type side DPC circuit
(b) H deflection current
(a) Left and right pin-cushion distortion
Fig. 12-2
V. Sync
H. Sync
3
13
9
10
4
2
Q501
V/C/DIC
TA1222N
Q302
E/W IC
TA8859P
PARABORA
VOLTAGE
GEN.
WAVEFORM
PROCESS
R343
9V
R465
R341
D464 D466
D465
Q461
-B
Q462
Q460
H. DY
H. out
FBT
+VB
Bus
control
(From
microcomputer)
AMP output circuit
S character
capacitor
Diode mdulator circuit
L461
C464
Содержание CF35E50
Страница 6: ...6 SECTION I OUTLINE ...
Страница 13: ...13 7 CN32D90 BLOCK DIAGRAM ...
Страница 16: ...16 SECTION II TUNER IF MTS S PRO MODULE ...
Страница 24: ...24 SECTION III CHANNEL SELECTION CIRCUIT ...
Страница 41: ...41 SECTION IV AUDIO OUTPUT CIRCUIT ...
Страница 44: ...44 SECTION V A V SWITCHING CIRCUIT ...
Страница 47: ...47 SECTION VI VIDEO PROCESSING CIRCUIT ...
Страница 52: ...52 SECTION VII V C D IC ...
Страница 55: ...55 SECTION VIII PIP MODULE ...
Страница 58: ...58 SECTION IX SYNC SEPARATION H AFC H OSCILLATOR CIRCUITS ...
Страница 63: ...63 SECTION X VERTICAL OUTPUT CIRCUIT ...
Страница 69: ...69 SECTION XI HORIZONTAL DEFLECTION CIRCUIT ...
Страница 85: ...85 SECTION XII DEFLECTION DISTORTION CORRECTION CIRCUIT Side DPC Circuit ...
Страница 92: ...92 SECTION XIII CLOSED CAPTION EDS CIRCUIT ...
Страница 98: ...98 SECTION XIV POWER CIRCUIT ...
Страница 109: ...109 SECTION XV DSP CIRCUIT ...
Страница 125: ...125 SECTION XVI FAILURE DIAGNOSIS PROCEDURES ...
Страница 139: ......