Sony TVP-08, Training Manual

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71
Sync Paths
Overview
The purpose of this slide is to show you the various sync signals and the
names for these signals. The RA-4 sync paths are more complicated
than normal due to the complexity of its operation.
Sync Paths
The Y signal is input to IC1305 Main Chroma Decoder. The main sync
signals are extracted from this signal and output at IC1305/14 VITM and
IC1305/15 HITM. The VITM signal is a 60 Hz signal called M-VD. The
HITM signal is a 15.734 KHz called M-HD. If the M-VD pulse is missing,
there will be no vertical sync. If the M-HD pulse is missing, there will be
no horizontal sync.
The M-VD and M-HD signals are input to the BM and BR boards. Each of
these boards outputs its own individual vertical and horizontal sync sig-
nals. These sync signals are input to IC509 Sync Select, which selects
the proper signals to be input to IC511 Video Processor. IC511 Video
Processor outputs the HS and VS signals, which will be used for syncing
the drive signals of the vertical and horizontal deflection circuits.
The VS signal is input to the BM board and IC512 VDSP. This IC creates
the vertical drive signal, which is output to the Vertical Output IC on the D
board. Normally the vertical blanking signal would be created using the
vertical boost pulse. Although this circuitry exists, it is not used since
R684 is not mounted. This is indicated by the # symbol. The VBLK signal
is created by IC512 VDSP instead. The BD board, IC511 Video Proces-
sor and the RGB Mute circuit use the VBLK signal. The VBLK signal is
also inverted by IC1003 and then called VP. The VP signal is used by the
CPUs in the set to time the I2C data. If this signal is missing and video is
applied to the set, a failure will occur that causes the power relay to cycle.
The HS signal is input to the BM board and IC507 H Jungle. The H Jungle
uses this signal to create the H drive pulse. The H Drive pulse is input to
the H Out. The H Out circuit creates a signal called HP. This HP signal is
used by IC507 to phase lock the H Drive and H Out signals. The BD
board and IC511 Video Processor also use it. The HP signal is sent through
IC1002 Buffer to be used by IC1009 OSD CPU and IC1004 OSD Proces-
sor.