Warped-Ragged Picture; Color Bar Test - Atari CX 5200 Field Service Manual

Warped -
Ragged
Picture
In
this failure,
the
power-up
screen appears bent
to
one
side
with a ragged edge.
The
picture
may
roll or slide
down
and to the
left of the screen.
This
means
that
the
sync,
signal
broadcast by
the
GTIA
is
probably not functioning. Another
possible
cause
is
that the
unit
is
not set on the
same
channel
as the T.V.
set.
Check
this
before going
to
the flowcharts.
Diagnostic Flowchart Entry
Point: Pg. 4-13.
COLOR
BAR
TEST
•
Purpose:
To
test the
GTIA
chip
and associated
color circuitry
for
correct
operation.
•
Format:
A
screen
of
horizontal color bars displays (see Figure
3-1).
The
screen should be steady
and
unchanging.
A
gray or blue horizontal
reference
line
runs across the
screen about three bars from
its
bottom.
This reference
line
is
thinner than
the bars around
it.
R8
should be
adjusted
so
the bars
immediately above and below
the reference
line
are
within
one shade
of
each
other.
Proper operation
of the unit
is
indicated
by being able
to
make
this
adjustment and by consistent color within the
entire
span
of
each bar on the
screen.
Minor glitches
on the edges of the
color bars are acceptable.
Leave
this
test
on
for at least
ten seconds
in
order
to
catch any intermittent problems,
such
as
a bar momentarily
changing colors or blanking out.
CX5200
Field Service
Manual
3-4