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
a
Purpose: To
test
the
GTlA
chip and associated color circuitry for correct
operation.
a
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
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