Revision as of 07:09, 16 January 2016

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)...

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 component

Turquoise "cold" image means no red
Purple image means no green
Orange "hot" image means no blue

Two missing components

Green and blue missing
Red and blue missing
Red and green missing

Three missing components

Enjoy the sound :)

Shorted components

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

Sync missing

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

@@ Line 1: / Line 1: @@
 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]])...
-The color test screen in the [[system ROM]] menu can help diagnose problems (burnt DAC resistors...).
+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 component=
@@ Line 22: / Line 24: @@
 Enjoy the sound :)
+=Shorted components=
+This can give very weird colors, since outputs will "fight" with varying strengths.
 =Sync missing=

Color issues: Difference between revisions