Color issues: Difference between revisions
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Incorrect colors can have various causes. In order of probability: bad JAMMA contacts or wiring, | 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 ( | The color test screen in the [[system ROM]] menu can help diagnose problems (burned DAC resistors...). | ||
Example screenshots are from [[Blue's Journey]]. | Example screenshots are from [[Blue's Journey]]. | ||
=One missing | To do: System ROM test mode monitor test screenshots. | ||
=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 | ||
| Line 12: | Line 14: | ||
</gallery> | </gallery> | ||
=Two missing | =Two missing colors= | ||
<gallery> | <gallery> | ||
File:rgbch_red.png|Green and blue missing | File:rgbch_red.png|Green and blue missing | ||
| Line 19: | Line 21: | ||
</gallery> | </gallery> | ||
=Three missing | =Three missing colors= | ||
Enjoy the sound :) | 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 {{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
-
Turquoise "cold" image means no red
-
Purple image means no green
-
Orange "hot" image means no blue
Two missing colors
-
Green and blue missing
-
Red and blue missing
-
Red and green missing
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.