Horizontal Centering (Raster Only) - Sony CPD-420GS Training Manual

Horizontal Centering ( Raster only )
The Micro IC1001 (N Board) controls the Raster position via the Horizon-
tal Centering circuit comprised of Q517, Q515 and IC502 (H CENT OUT).
The Horizontal Centering ( Raster only ) can only be adjusted using the
DAS Software. IC1001 outputs Horizontal Centering voltage on pin 4 via
CN1001/30 to CN801/30 (H.CENT) on the D Board. The H.CENT volt-
age is applied to Q517 buffer and is then applied to Q515 H CTR CTRL.
Q515 inverts and amplifies the H.CENT voltage and is input to IC502/2 (-
). When Horizontal Centering is adjusted, the voltage input to IC502/2 (-
) varies and as a result the output of IC502/4 (O) also varies. The output
of IC502/4 (O) via R541, R546 and L503 applies a positive or negative
DC offset to the Drain of Q506 H SIZE REG OUT. This DC offset moves
the Raster position left or right of center. Q802 and Q516 are controlled
by the 'REMOTE ON/OFF' command to mute the input to IC502 during
power save.
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Caution: IC502 is powered by a floating supply. Do not attempt to check
voltages at IC502 with an O-Scope by attaching a ground lead to T601/17
(floating ground). This may result in damage to IC502. Use a DVM when
verifying voltages around IC502.