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

[Zippster]

Hi John,

Are you running with or without the ground fix on the hsync input?

- Ed


> On Jul 19, 2015, at 8:41 PM, John B <trymyz at gmail.com> wrote:
> 
> 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!!!
>>>>>> 
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>>>>> 
>>>>> 
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>>>> 
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>> 
>> 
> 
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