[Coco] Cross Post from the Facebook Page about the RGB2VGA Board

[John B]

Steve,

I built a second board this weekend with the new resistor values.  Your
sheet was quite handy.  Thank you again.  The text has definitely
stabilized but a few other things are off.  The left edge of the screen is
kind of wavy and gray lines are wavy.  For example in KQ3, everything else
is stable, except the gray lines (lines in the stairs and wall).  They seem
to shimmer.  I have adjusted the potentiometer but going to far either way
causes other issues with the image.  I know you recommeneded a multi-turn
potentiometer.  Which one are you using?  Anyway, I will most likely try a
higher quality monitor and see if the image improves.  Currently I am using
a cheap Dell 17 inch that was in the attic.  Maybe I am being too picky and
this is as good as it gets.

John

On Sun, Jul 12, 2015 at 4:53 PM, John B <trymyz at gmail.com> wrote:

> I am pretty sure it will stabilize with new resistor values.  Compared to
> composite, it looks pretty darn good now.  OSH Park only sold the boards in
> lots of 3 so I have 2 spares.  I will definitely complete the other one
> with the new values.  Haven't decided if I will build the third one yet.
>
> On Sun, Jul 12, 2015 at 1:04 AM, Steve Batson via Coco <
> coco at maltedmedia.com> wrote:
>
>> John,
>>
>> Trust me, unless you have something else wrong with the board, Roger's
>> recommended resistor changes will clean things right up. Mine looks awesome
>> and I simply duplicated his changes. Since I had a few resistor changes, I
>> may end up buying another board and building one up fresh with the right
>> resistors the first time. The board will certainly look better and it won't
>> hurt to have a spare. I'm not going to buy a spare FPGA
>> though...hehehehe...that's a bit pricey.
>>
>> On Jul 11, 2015, at 9:48 PM, John B <trymyz at gmail.com> wrote:
>>
>> > Definitely great news.  Hopefully the new resistors will take care of my
>> > jitter/wavy lines and text problem.  I will find out next week.
>> >
>> > On Sun, Jul 12, 2015 at 12:42 AM, Steve Batson via Coco <
>> > coco at maltedmedia.com> wrote:
>> >
>> >> I changed the last 4 resistors and didn't really notice much
>> difference,
>> >> but since values were based on Roger's research and testing and that
>> his
>> >> board is now solid, I figured I'd do the same. I've Tested all of the
>> >> features and it's incredible results.
>> >>
>> >> The output is rock solid. Colors are Rich. Text looks fantastic in 32,
>> 40
>> >> and 80 columns. I've tested Zaxxon, Grabber, Tetra3, Brewmaster, Donkey
>> >> King. And The biggie, Sockmaster's port of the Original Donkey Kong
>> and it
>> >> Looks Awesome! Very happy with the results of this thing. It was a lot
>> of
>> >> work, but it was well worth it.
>> >>
>> >>
>> >>
>> >>
>> >> On Jul 9, 2015, at 8:45 PM, Steve Batson <steve at batsonphotography.com>
>> >> wrote:
>> >>
>> >>> I figured I'd post the following here too. Some discussion occurred on
>> >> the FB page, but a lot of discussion was done between Roger and Myself
>> in
>> >> email as Roger made several discoveries that stabilized some very
>> annoying
>> >> jitter problems with video.
>> >>>
>> >>> RGB2VGA Stabilized!
>> >>> First thanks to Felipe for a very cool Solution to bring the CoCo3
>> video
>> >> to Modern VGA Monitors. Originally, I missed a few resistors that I
>> somehow
>> >> thought were optional and Felipe straightened me out on those.
>> >>> Then I was getting Jitter just like Roger was experiencing. I had
>> >> several email discussions with Roger as he was doing some research and
>> >> experimenting based on what he found about the VGA standards and found
>> that
>> >> changing some resistor values stabilized the output from his board. I
>> have
>> >> pretty much duplicated Roger's resistor values on my board with the
>> >> exception of 4 that I'm waiting to come in, but mine is crisp and
>> jitter is
>> >> gone. I will most likely change those 4 resistors when the parts come
>> in
>> >> unless it doesn't make sense.
>> >>> Anyway, Finally fantastic output on my VGA monitor. Very Cool!!!
>> >>> Very Big thanks to Roger!!!
>> >>>
>> >>> --
>> >>> Coco mailing list
>> >>> Coco at maltedmedia.com
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>> >>
>> >>
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>> >>
>> >
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>>
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>