RE: SEGA G80 - Star Trek Draw Problem..

You said that the line shows on your scope (assuming you are controlling X/Y thru channels, and green is connected to Z)?

What happens when you swap the color lines to the monitor? Does the green channel drop out completely even when driving another color?

When you go into self test, does the white line that follows the upper right stay white all the way around? Can you post a pic of your screen?

From: owner-vectorlist@vectorlist.org [mailto:owner-vectorlist@vectorlist.org] On Behalf Of Douglas Gauck
Sent: Tuesday, April 03, 2012 3:41 PM
To: vectorlist@vectorlist.org
Subject: Re: VECTOR: 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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Received on Tue Apr 3 20:13:12 2012