[Coco] [HW] Coco 3 video output corrupt when using cart port

[Mike Pepe]

I would also suggest using one of the other outputs to see if the
problem follows the CoCo or is specific to that particular monitor.

1702's are pretty vintage these days.


> -----Original Message-----

> From: coco-bounces at maltedmedia.com [mailto:coco-

> bounces at maltedmedia.com] On Behalf Of Brian Sturk

> Sent: Friday, February 20, 2009 4:21 PM

> To: CoCoList for Color Computer Enthusiasts

> Subject: Re: [Coco] [HW] Coco 3 video output corrupt when using cart

> port

> 

> Hi Robert,

> 

> Thanks for the ideas.  The fringing seems to be on a 40 columns.

> I sent an email out a little while ago thinking a warm reset helps but

> not it's not exhibiting the issue anymore.  I wonder if it's thermal

> related (i.e. being on for a certain amount of time?).

> 

> I'll try and narrow something down...

> 

> ~telengard

> > Brian Sturk wrote:

> >

> >>   On a black screen I can see hints of orange and blue.  It's

almost

> >> like random repainting of the screen *and* the magnetic field

> >> effect.  Definitely weird.

> >>

> >> thanks for the help, I'll report back,

> >> ~telengard

> >>

> >

> > As Tim suggested, re-seating all socketed chips is a good idea even

> if

> > it does not help with this problem. Tandy did not use gold plated

> > contacts so a fresh surface can't hurt and could help.

> >

> > The orange and blue, is that fringing around text with a 40 or 80

> > column screen? If so, it is artifact colors typical of composite

> > video. Some screen colors will make the effect worse than others.

> > There is only one way to get rid of it completely and that is by

> > patching Basic.

> > If this is the source of your colors, I'd suggest using a 40 column

> > screen with a white background and black letters. Enter

> > WIDTH40

> > CLS5

> >

> > If the orange and blue is artifacts and you get a disk system to

make

> > it easy to SAVE and RUN programs, the following will turn off the

> > color burst signal and remove artifacts.

> >

> > 10 POKE&HE033,16:REM width 32 screen

> > 20 POKE&HE03C,19:REM width 40 screen

> > 30 POKE&HE045,19:REM width 80 screen

> >

> >

> > --

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> > Coco at maltedmedia.com

> > http://five.pairlist.net/mailman/listinfo/coco

> 

> 

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> 

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