Why do Genlocked White Areas Show Wrong Color on AGA Systems?

CBaldoni

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Genlocked White Areas Show Wrong Color on AGA Systems

Genlocked White Areas Show Wrong Color on AGA Systems


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Product: Video Toaster, Flyer

Platforms: 2000 3000 3000T 4000 4000T

Platforms: A4000 (possibly A4000T)

Problem: White areas of genlocked Amiga graphics show up the wrong color on AGA Chipset Systems.


If genlocked Amiga graphics, such as the AGA color animated effects, show as purple, pink or grey where they should be showing white area, the difficulty is usually the voltage regulator at position U198. This is 7905 voltage regulator which converts -12V to -5V and feeds that to the expansion bus connector. The part is not surface mount, so it is relatively easy to replace. On the 4000 desktop model this part is located about one inch inward from the keyboard connector on motherboard.

Commodore usually used a part rated at 100 milliamps which was marginal for the demand on the part in actual use. Replacement with a part rated at 200 - 300 milliamps would be recommended.


See also: Pink Scrolls and Crawls from CG
 
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