Path: utzoo!attcan!uunet!cbmvax!hood
From: hood@cbmvax.commodore.com (Scott Hood)
Newsgroups: comp.sys.amiga
Subject: Re: Amiga 3000 flickers?
Keywords: A3000 Display Enhancer
Message-ID: <13260@cbmvax.commodore.com>
Date: 17 Jul 90 21:26:45 GMT
References: <1990Jul14.043408.20134@cunixf.cc.columbia.edu> <5144@ethz.UUCP>
Reply-To: hood@cbmvax (Scott Hood)
Organization: Commodore, West Chester, PA
Lines: 34

In article <5144@ethz.UUCP> visinfo@bernina.ethz.ch.UUCP (VISINFO c/o Peter Simeon) writes:
>In article <1990Jul14.043408.20134@cunixf.cc.columbia.edu> es1@cunixb.cc.columbia.edu (Ethan Solomita) writes:
>>
>>	Just a little quirk about the A3000 that happens to me
>>and someone else as well. The left half of the top scan line on
>>the screen flickers. It is only one scan line, so it seems very
>>wierd. Any explanation or way to stop it? It isn't the monitor,
>>since I've moved the image around on the screen and it is still
>>there. I've also used the same cable on my A2000 without problem.
>
>Every Amiga 3000 i've seen had this flicker in first line. I suppose that's
>a "feature" of the display enhancer. It looks like the display enhancer
>is turned off in the first line and that it has to check wether it has
>to deinterlace or scan double. Could someone at Commodore confirm this?
>
>You can only stop it if you disable interlace or if you open a productivity
>screen.
>

This is due to how the current Amber chip does the de-interlace
function.  On 1950 monitors which allow the user to put the black
borders behind the bezal of the monitor, the user will never see this
video artifact.  On other multiscan monitors that don't allow the user
to adjust the size of the screen this top line is visible.  It is only
present when de-interlacing the Amiga's interlaced display modes.   

Scott      


-- 
--
Scott Hood, Hardware Design Engineer (A3000 Crew),  Commodore-Amiga, Inc.
   {uunet|pyramid|rutgers}!cbmvax!hood   hood@cbmvax.cbm.commodore.com
  "The views expressed here are not necessarily those of my employer!"