Re: SEGA G80 - Star Trek Draw Problem..

From a practical standpoint since U2 was bad I'd check U13 before it and U1 after it, but it feels like an analog problem since it doesn't correspond to a discrete quadrant of the screen, or a bit value. How about D1 and D4? Yikes.

-Douglas

Sent from my iPhone

On Apr 3, 2012, at 1:48 PM, Arcadius Stempak <arcademanx@yahoo.com> wrote:

>
> Thanks to everyone for your feedback and input, appreciate it...
>
> The ' color information ' makes me wonder if the screen is somehow divided up (either in memory or
> in some other fashion) with reference to how the Display is drawn ? Well, actually what little I do know
> is that the screen is divided in 4 Quadrants (from what I have read on line - with regard to ' byte 4 ' (see below)============================================================================
>
> Line Instructions ( 4 bytes / line )
>
> byte 1 <last line, color, unblank> L R R G G B B D
> ^ ^
> | +-visible
> +-last vector
>
> byte 2 length vector length
>
> byte 3 line angle vector angle
>
> byte 4 screen quadrant (0-3) direction to draw
>
> 2 | 3
> --+--
> 1 | 0
>
> ============================================================================
> But my main issue, is, (assuming that somehow (maybe) Quadrants 2 and 3 (or portions of)) are missing
> color, what on the Control Board, actually controls the information present within this section?
>
> Its almost as if the color ' Green ' is either missing or ' blanked out ' within this portion of the screen for some reason?
>
> On a sidenote, since I have swapped ' RAM ' I also wondered if perhaps one or more of the Sockets may be suspect?
> But after looking these over repeatedly I see no ' dirt ' or any other issues, I.E. bent pins, etc.. in any of these scoekts.
>
> Oh well, will keep on digging into this.
> Appreciate any and all input or ideas.
>
> Regards,
> _Arcadius
>
> From: Kevin Moore <talon.k@gmail.com>
> To: vectorlist@vectorlist.org
> Sent: Monday, April 2, 2012 4:22 PM
> Subject: Re: VECTOR: SEGA G80 - Star Trek Draw Problem..
>
> The only time I've seen anything similar it was a ha color ram but then that was in a tempest.
> On Apr 2, 2012 4:14 PM, <kstillinger@sc.rr.com> wrote:
> That's a pretty odd one.
>
> Your description makes it sound like the vectors are still in the output, but without color information.
>
> I don't know what would cause this, especially on a single color and on ONE section of the screen.
>
> I've seen some boards that still put out the XY signals, but if the color is missing, nothing shows up.
>
> Kerry
>
>
> ---- Arcadius Stempak <arcademanx@yahoo.com> wrote:
> > All,
>
> After some troubleshooting into this issue (which affects the G80 - Control Card - only),
> I was wondering if anyone else may have run into this, since I am pretty much out of ideas.
>
> Ok so here is the scenario..
>
> Original problem:
> Complete lack of the color Green - missing lines - since resolved by replacing U2 on the Control Card.
>
>
> Current problem:
> While the color Green is now present in the middle and lower sections of the Monitor
> (imagine diving the screen into 1/3 rd's) and there is no problem with Line Draw, etc.
>
> Main problem is that the color Green is missing (not at all present and all Green Lines are not being Drawn
> in the Upper 1/3 rd of the screen). This includes the Gauge on the Upper left hand side of the screen, which is
> also missing the Green Lines and Triangle indicator.
>
> However, when I hook up the X/Y Outputs to an Oscilloscope All Lines are present (but only in black and
> white).
>
> Also swapping Control Cards with a Good Set - displays All lines / Colors correctly - so not a monitor issue.
>
> After replacing the Memory (which did not change anything), any ideas as to what could be causing this issue?
> Or better yet what on the Control Board, corrolates to ' Draw ' and the color ' Green ' / upper 1/3 or the screen ?
>
> Appreciate your help,
>
> Regards,
> _Arcadius
>
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>

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Received on Tue Apr 3 16:43:55 2012