[Coco] CoCo bus interface project

Mark Marlette mmarlette at frontiernet.net
Mon Apr 15 18:46:42 EDT 2013


Felipe,

Very few wall warts I have seen are very regulated or filtered.

If you have a scope/meter you can see how clean the output is. A 60hz bounce on the PS might cause all kinds of problems.

Just a thought....

Regards,

Mark




________________________________
 From: Luis Antoniosi (CoCoDemus) <retrocanada76 at gmail.com>
To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com> 
Sent: Monday, April 15, 2013 3:14 PM
Subject: Re: [Coco] CoCo bus interface project
 

Yours looks the same as mine: GBS8200:
http://en.gonbes.com/product_detail.asp?menuid=94&id=22

It will try the same at home. I use a 5V 2A wall wart but it keeps bouncing
the image and sometimes loses completely the sync. Thuis board accepts the
YCbCr from the Coco2 wich looks awesome but this bouncing thing made me
ditch it in the basement. I'll try to use it again.

I found this article with interesting info.

http://forum.arcadecontrols.com/index.php?topic=123399.0

Felipe.



On Mon, Apr 15, 2013 at 4:09 PM, Matthew Stock <stock at csgeeks.org> wrote:

> On Mon, Apr 15, 2013 at 3:41 PM, Luis Antoniosi (CoCoDemus) <
> retrocanada76 at gmail.com> wrote:
>
> > Hi Matthew,
> >
> > I can see you use a GBS8200 to convert the coco3 rgb. I have one but
> image
> > skips a lot. Seems to be related to grounding. I can see you're using the
> > power molex to connect something else,
> >
> > i could tell you got the ground from PSU and connected to the RGB input
> > ground, is that right ?
> >
> >  Did you do something to fix the freaking bouncing screen ?
> >
> >
> If I did something, it was probably accidental.  :-)
>
> I took a switched 5v wall wart I had lying around, and I attached it to a
> barrel connector to provide power to the board.  I also needed power for
> the composite sync board, and so followed the path of least resistance and
> used the molex connector on the GBS board as an INPUT for that sync board.
> The GBS board has a wider input range, but I need to remember to only feed
> it 5v for this reason.  You're correct that I tie the power and signal
> grounds together (so common ground for coco and GBS).
>
> There are a few different variants of the GBS board.  I can look tonight
> and see what specific version I have and let you know.
>   -Matt
>
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>



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