Colour Decoder; On-Screen Display - Hitachi C1422R Service Manual

Colour Decoder

The luma signal processing and colour decoding are implemented by I501. The luminance and chrominance
signals are separated internally. A delay line is also incorporated to compensate for the difference between
the luma and chroma processing times. There are no adjustments required on the colour decoder.

On-Screen Display

The micro-controller on-screen display (OSD) supplies blanking and RGB signals for overlaying the
television picture. Pin 35 of I701 provides blanking pulses which are applied to pin 26 of I501 via Q301, to
turn off the decoder RGB output so that the OSD is clearly visible. The RGB signals from pins 34, 33 and 32
of I701 are applied directly to the tube-base via Q306 to Q308 and the text drive colour balance presents
R317 and R319.
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