Color issues: Difference between revisions

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Incorrect colors can have various causes. In order of probability: bad JAMMA contacts or wiring, broken SCART cable, monitor failure, damaged [[video DAC]], bad [[palette RAM]], cut traces between [[GPU]] chips (check [[P bus]])...
Incorrect colors can have various causes. In order of probability: bad JAMMA contacts or wiring, split SCART cable, monitor failure, damaged [[video DAC]], bad [[palette RAM]], cut traces between [[GPU]] chips (check [[P bus]])...


The color test screen in the [[system ROM]] menu can help diagnose problems (burned DAC resistors...).
The color test screen in the [[system ROM]] menu can help diagnose problems (burned DAC resistors...).
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To do: System ROM test mode monitor test screenshots.
To do: System ROM test mode monitor test screenshots.


=One missing component=
=One missing color=
<gallery>
<gallery>
File:rgbch_nored.png|Turquoise "cold" image means no red
File:rgbch_nored.png|Turquoise "cold" image means no red
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</gallery>
</gallery>


=Two missing components=
=Two missing colors=
<gallery>
<gallery>
File:rgbch_red.png|Green and blue missing
File:rgbch_red.png|Green and blue missing
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</gallery>
</gallery>


=Three missing components=
=Three missing colors=


Enjoy the sound :)
Enjoy the sound :)


=Shorted components=
=Shorted color lines=


This can give very weird colors, since outputs will "fight" with varying strengths.
This can give very weird colors, since outputs will "fight" with varying strengths.


=Sync missing=
=Missing sync=


Rolling or distorted display, most probably a bad contact. If not, check {{Sig|SYNC|SYNC}}.
Rolling or distorted display, most probably a bad contact. If not, check {{Sig|SYNC|SYNC}}.

Latest revision as of 09:13, 4 April 2016

Incorrect colors can have various causes. In order of probability: bad JAMMA contacts or wiring, split SCART cable, monitor failure, damaged video DAC, bad palette RAM, cut traces between GPU chips (check P bus)...

The color test screen in the system ROM menu can help diagnose problems (burned DAC resistors...).

Example screenshots are from Blue's Journey.

To do: System ROM test mode monitor test screenshots.

One missing color

Two missing colors

Three missing colors

Enjoy the sound :)

Shorted color lines

This can give very weird colors, since outputs will "fight" with varying strengths.

Missing sync

Rolling or distorted display, most probably a bad contact. If not, check SYNC.