[Coco] [Color Computer] Re: The Best Monitor for a CoCo 3 is a TV. (Really!)

[James Diffendaffer]

Just check the specs on the Analog Devices chip.  The CoCo may not
output the proper frequency for that chip.


> While I was working on a absurd project to display ATSC HDTV from my
HTPC
> on my NTSC RCA TV I realized that the same solution could be used
with the
> CoCo 3.
> 
> Some newer TV's have a S-Video input which bypasses the TV circuits used
> with Video input which degrade the picture immensely.
> 
> The "MyHD" HDTV PCI card in my HTPC can produce a 480i(720x480
interlaced,
> 15.75kHz) RGB (VGA) output.
> 
> This is not a S-Video signal but can be converted by a chip produced by
> Analog Devices.
> 
> The CoCo 3 produces a similar RGB output.
> 
> The CoCo 3 S-Video display on my TV is as good as the display on the
Sony
> KV-1311CR.
> 
> As the screen is larger many persons (Gamers) will prefer the larger TV
> S-Video displays.
> 
>
---------------------------------------------------------------------------
> 
> Analog Devices has a "AD72x" series of chips that I expect all will
do an
> excellent job of converting the CoCo 3's RGB output to S-Video.
> 
> I used the AD723 for my project.
> 
> AD720
> 
> AD721
> 
> AD722
> 
> AD723 $4.12 (#100)
> 
> http://www.analog.com/en/prod/0,2877,AD723,00.html
> http://www.analog.com/UploadedFiles/Data_Sheets/774020909AD725_0.pdf
> 
> AD723 Evaluation Board $75.00
>   The links on www.analog.com for the Evaluation
>   Board are circular and all lead to the basic AD723 pdf.
>   This is true for pages found in the time machine archive
>   and also for 3rd party repositories of data sheets.
>   Hopeful a copy is included with the evaluation board.
>   The original owner of my AD723 evaluation board cannot find a copy.
> 
> AD724 $6.26 (#100)
> 
> http://www.analog.com/en/prod/0,2877,AD724,00.html
> http://www.analog.com/UploadedFiles/Data_Sheets/40671345AD724_b.pdf
> 
> AD724 Evaluation Board $125.00
>
http://www.analog.com/UploadedFiles/Evaluation_Boards/Tools/452661188AD724eb.pdf
> 
> AD725 $5.31 (#100)
> 
> http://www.analog.com/en/prod/0,2877,AD725,00.html
> http://www.analog.com/UploadedFiles/Data_Sheets/774020909AD725_0.pdf
> 
> AD725 Evaluation Board $245.00
>
http://www.analog.com/UploadedFiles/Evaluation_Boards/Tools/120333814AD725eb.pdf
> 
> The Evaluation Boards are assembled with cables. All that you need
to add is
> a CoCo 3 RGB cable with a DB15 VGA connector and a connection to a
3-5 volt
> power supply. Three ~100 ohm resisters need be inserted in the R, G
and B
> lines.
> 
> -------------------------------------------------------------
> 
> For the CoCo 3 I recommend that a AD724 be used. This chip has 16 leads
> instead of the 28 on the AD723.
> 
> Fewer pins mean fewer problems
> 
> There is a site with a single sided PCB that is a good starting point.
> Changes need to be made, NTSC instead of PAL and S-Video output.
> 
> Coelho's Site - VGATV Hardware Page [AD724 by Ludovico Caledon]
> http://pwp.netcabo.pt/pscoelho/vgatv/ludovico/LC-AD724.html
> 
> Drawn using Eagle 4 for Linux.
> 
> -------------------------------------------------------------
> 
> All the AD72x chips need the same external parts.
> 
> I expect that an evaluation board is really not needed in the
development of
> a board for the CoCo 3. There are just not too many things that can
go wrong
> and no adjustments are needed.
> 
> -------------------------------------------------------------
> 
> My CoCo 3 plans: To answer questions and offer advise.
> 
> As I have the Sony KV-1311CR for use with the CoCo 3 and an additional
> computer monitor that could be used, I have no real need for
> continuing with this project.
> 
> Now for the non-believers.
> 
> I have taken some digital photos of several CoCo 3 generated screens.
> 
> Taking digital photos off a TV screen has problems that are not
visible to
> an human eye looking at the screen.
> 
> The raster lines appear to be too prominent. In normal viewing you
will want
> to be farther from the TV due to its larger size.
> 
> There is interference that shows up on some of the photos. Again I
say that
> a human looking at the screen will not observe this.
> 
> I suggest that you download the Index first
> 
> "IndexSV.jpg" 204,464 Bytes
> 
> and then
> 
> "P0001814.jpg" 447,272 Bytes.
> 
> This is the CoCo 3 64 colors all on one screen display.
> 
> These photos are ones that you download and look at for 30 seconds
once and
> never look at them again.
> 
> So please be kind to Dennis and not abuse his bandwidth.
> 
> ftp://maltedmedia.com/coco/CC3/Monitors/Svideo/
> 
> -----------------------------------------------------------------
> 
> Can I expect the same great display on my S-Video TV?
> 
> Yes, TV's with S-Video inputs tend to be larger, better designed and
better
> built.
> 
> How much does a S-Video TV cost?
> 
> Will you believe Cheap or FREE!
> 
> We in the USA are in the process of turning off the analog NTSC TV
broadcast
> transmitters and having only digital ATSC OTA transmitters.
> 
> This will make a huge number of old TVs need to be replaced with
HDTV sets.
> In Silicon Valley all the Analog stations now are also transmitting
digital
> signals with very few exceptions. Even the Praying, Shopping and Spanish
> stations.
> 
> So when a friend says that they are going to get a new HDTV, talk to
them
> about their old set. Do not wait. Those persons that have purchased TV's
> with S-Video inputs are the ones that will or already have purchased
a new
> HDTV.
> 
> -----------------------------------------------------------------
> 
> The "CoCoList for Color Computer Enthusiasts " is a lively list of
CoCo'ers
> that have many projects ongoing and can answer just about any question
> about CoCo's.
> 
> If you are not a member and wish to join us, download the file
> "JoinCoCo.txt" from the S-Video folder with the pictures listed
> above.
> 
> -- 
> Stephen H. Fischer




Brought to you by the 6809, the 6803 and their cousins! 
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/ColorComputer/

<*> To unsubscribe from this group, send an email to:
    ColorComputer-unsubscribe at yahoogroups.com

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/