Arcam DiVA DV78, Service Manual

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Video Output stage
The DV78 video output stage makes use of the
VADDIS V’s on board video DAC stages and as such
does not use the superior Analogue devices video
encoder DV79/DV29 and is fed by the following video
lines from the Vaddis V.
o
Composite
o
SVID_C
o
SVID_Y
o
V or Red
o
U or Blue
o
Y or Green
If we look at the Composite stage only, we will see that
the Analogue video signal is filtered by C710, C711
and L705 before being passed through the Video Op-
amp at location IC701 the output is decoupled by
capacitor C738 before reaching R714 this forms the
75 ohm load required. All other video outputs are
identical.
SCART Output
RGB and Composite video signals as well as Left and
right audio signals are all present on the SCART
output socket. As the RGB and YUV signals share the
same output port at the Vaddis V the player must be
set to RGB SCART operation to have a RGB output
on the SCART.
Please note : When in RGB SCART mode the RGB
does not contain a Sync signal and the sync must be
taken from the Composite out (4 wire RGB).
Also present at the Scart are a number of control flags
for the monitor these include 2 GPIO control lines
direct from the Vaddis.
o
ENABLE_AV
o
16/9
These are seen at the SCART output pins as.
o
O/6/12
o
RGB STAT
The 0/6/12 line (SCART pin 8) is used to inform the
monitor of the screen format being sent by the player
as set in the video set-up section of the software.
o
Standby = 0V
o
16:9 aspect ratio = 6V
o
4:3 aspect ration = 12V
The RGB status line (SCART pin 16) will be seen as
0v = no RGB and >1v is RGB present.