Horizontal Deflection; Horizontal Drive - Sony CPD-420GS Training Manual

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Horizontal Deflection

Overview
The Micro IC1001 and DSP IC1002 (N Board) respond to the Timing and
Sync parameters of the video inputs and provide the necessary Horizon-
tal Drive and Geometric correction waveforms for the Horizontal Deflec-
tion circuit on the D Board. Horizontal Deflection and High Voltage is
controlled by IC805 HV / H SIZE REG CTRL. IC805 produces PWM
(Pulse Width Modulation) drive outputs to control for Size, Bow, Pincush-
ion and Keystone. Control for linearity, centering and impedance match-
CN801/26 HD OUT
ing are also part of the Horizontal Deflection circuit.

Horizontal Drive

I
C1002 (N Board) outputs Horizontal Drive on pin 25 (H-OUT) via CN101/
26 to CN801/26 (HD OUT) on the D Board. The HD OUT signal is applied
to Q501 H Drive buffer. Q501 shapes, amplifies and inverts the HD OUT
signal and is applied to Q502 and Q503 Push-Pull H Drive buffer. Q502
and Q503 amplify the HD OUT signal and is applied to Q504 H Drive.
The -16V DC supply is applied to Q504/S and the Drain of Q504 is at 0V
DC via T501 to ground. Q504 drives T501 HDT (Horizontal Drive Trans-
former) which provides base current to Q505 H OUT. Q505 collector
produces approximately 1kV P-P spike to drive the positive side of the Q505/C
Horizontal Deflection Yoke (H DY+) through T504 HST (Horizontal Size
Transformer). The negative side of the Horizontal Deflection Yoke (H
DY-) is AC coupled to ground via L502 HLC (Horizontal Linearity Coil),
T503 LCT (Linearity Coil Transformer), L505, R522 and C513.