Color Bar Test 3A-4 - Atari CX 5200 Field Service Manual

COLOR BAR
TEST
•
Purpose: To
test
the
GTIA
chip
and
associated color circuitry
for
correct
operation.
• Procedure: Press
key
2
followed by
START.
•
Format:
A
screen
of
horizontal color bars displays (see
Figure 3A-1). The
screen should be steady and
unchanging.
A
gray or
blue horizontal
reference
line
runs across the screen
two
bars
from the
bottom
of the
screen.
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.
Diagnostic Flowchart Entry
Point:
Pg. 4A-14.
NOTE:
This figure
is
a black
and white representation of a color television screen.
Figure 3A-1. Color Bars Screen
CX5200
Field
Service
Manual
3
A
-4