The operator must verify that:
• Each of the 12 players, missiles, and playfields is distinct (separated by gray
background).
• 8 luminance levels (black to white) are shown.
• All colors are present and uniform across the screen.
• The players and missiles in the middle of the screen move up and down.
• The color tuning bar is one solid color. If the color is out of adjustment, another color
bar will show inside the tuning bar. Adjust the trim pot until this smaller bar
disappears (can be reached from hole in housing bottom). It will be noted that the
colors do not exactly align horizontally. This is acceptable. The operator should reject
machines with problems such as:
Missing/overlapping players, missiles or playfields.
Flecks of (wrong) color at the margin of players, missiles or playfields.
Gaps in the luminance or color bands (except the 5th gray bar and 1st color
bar, which are the same as the background color).
These problems likely indicate a bad GTIA chip.
Figure 3-8. VIDEO Test display
PORT
The top of the screen will go blank until the test is completed. PASS or FAIL will be printed.
If the test fails, one or more error codes will be displayed. Make note of the error code and
press the space bar to continue with the next test.
130XE Personal Computer
Field Service Manual 3-6
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