Composite Video from a TRS-80 Coco 1?
Leif Bloomquist
I got a Coco1 for very, very cheap on eBay ;-) This is the specific model:
http://en.wikipedia.org/wiki/Image:TRS-80_Color_Computer_1.jpg
I tested it with my TV and VCR, and it works very well. But, just to save
space, I'd much rather use it with my Commodore 1701 monitor, which has
composite video in only.
What's the best way to get composite video from the Coco 1? Is there a
convenient place to tap the video from the circuit board (i.e. before it
reaches the RF modulator)? Or should I just get an external TV tuner?
It's NTSC if that makes a difference.
Thanks
Leif
--
Leif Bloomquist
leif(at)schemafactor(dot)com
http://home.ica.net/~leifb/
"Once secure, saturate the area with plasma mortars and spicy barbecue
sauce."
motococo
<sp...@127.0.0.600> wrote:
> What's the best way to get composite video from the Coco 1? Is there a
> convenient place to tap the video from the circuit board (i.e. before it
> reaches the RF modulator)? Or should I just get an external TV tuner?
> It's NTSC if that makes a difference.
Hiya Leif,
I have a grey case CoCo 1, a white case 64K CoCo 1, a couple of CoCo 2's,
and a CoCo 3. What I do is this:
I hook up any of the above said CoCo units via an adapted coaxial cable
(RCA male to coaxial female adapter at the CoCo RF modulated output) and
plug the other end of the coaxial cable into the coaxial IN of my Radio
Shack 15-1981 Cable Converter box (setting the coverter box to the same
channel as the CoCo's RF output channel setting.....that being either
Channel 3 or 4).
Then, I output the audio/video outputs on the back of the 15-1981 Cable
Converter box to the appropriate audio/video inputs of my Commodore 1702
or my Commodore 1084 monitor.
I get awesome crystal clear composite video this way, even with the CoCo
3. Yes, even with the CoCo 3.
As a matter of fact, when I hook up the CoCo 3 in the above manner, it
gives me a better more crisp and more vibrant composite display that when
using the CoCo 3's built in composite video output. Go figure!!! Of
course, I built an RGB adapter cable to output the CoCo 3's RGB to my
Commodore 1084 analog RGB input, so it's kinda a moot point with the CoCo
3 in my case. But it's still nice to do when I need to run those blasted
artifacting PMODE4 games on my CoCo 3 which show up black and white via
RGB.
But in any event, all my other composite video challenged CoCo 1's and
CoCo 2's are able to display very nice clear composite video using my
above method, and with no need to hack up the internals of the CoCo's to
do so.
Your mileage may vary with other cable converter boxes (and not all cable
converter boxes necessarily will have composite video outputs). I can
only mention the Radio Shack 15-1981, as that's the only one I own and
have tried.
I bought the 15-1981 box brand new at a Radio Shack here in Winnipeg,
Manitoba, Canada back in 2001, when there were still Radio Shack stores
here, before most of them changed to "The Source by Circuit City" stores.
Don't know if The Source stores carry something similar or not, but you
may try. Or perhaps if you live in the U.S. your local Radio Shack stores
may still carry such a cable convertor. Just make sure it has composite
video output on the back of it.
I also purchased the RCA male to Coax Female adapter(s) at Radio Shack.
Note: I used a good quality shorth length (approximately 4 feet) of RG6
Quad Shield Coaxial Cable, the kind that my StarChoice satellite installer
left me as a bonus.
Of course, if you want to tap the video directly from the CoCo's circuit
board, there are ways to do that to, but I have never tried it personally.
Since my setup with the coax converter box works so perfect, I see no
reason to hack up the internals of my otherwise mint condition CoCo's.
Hope this info helps.
best regards
N Morrison
Leif Bloomquist wrote:
> What's the best way to get composite video from the Coco 1? Is there a
> convenient place to tap the video from the circuit board (i.e. before it
> reaches the RF modulator)? Or should I just get an external TV tuner?
>
> It's NTSC if that makes a difference.
http://coco_docs.tripod.com/id26.htm : Color Monitor Driver
tim lindner
I've built that. It worked as advertised.
--
The ears are too length.
--------------------------------------------------------------
tim lindner: First initial last name at macmess dot org
Petrander
I have a CoCo2 that was hacked by someone to enable composite video.
When it failed working I put out some schematics on the internet to get
some help. Maybe these are helpful to you too:
http://www.coco3.com/gallery/v/User+Albums/CoCougar/BrokenCoCo2/
Cheers,
Fedor Steeman - CoCo enthusiast
Leif Bloomquist schreef:
Leif Bloomquist
news:1166578352....@i12g2000cwa.googlegroups.com...
> http://coco_docs.tripod.com/id26.htm : Color Monitor Driver
Thanks everyone. I did find a standalone video demodulator box which works
reasonably well, but this circuit looks like it is the best way to go.
The article mentions another circuit in a previous article that does
monochrome video as well as audio. I'll need audio as well, does anyone
have a copy of that article (page 36 of HOT Coco, July 1983), or know a way
I can get audio? Is there a place on the motherboard I can simply pick it
off?
I found the Coco1 technical manual online, but it wasn't clear whether the
audio was at usable levels on the board.
Thanks again,
Leif
N Morrison
Leif Bloomquist wrote:
> The article mentions another circuit in a previous article that does
> monochrome video as well as audio. I'll need audio as well, does anyone
> have a copy of that article (page 36 of HOT Coco, July 1983), or know a way
> I can get audio? Is there a place on the motherboard I can simply pick it
> off?
>
> I found the Coco1 technical manual online, but it wasn't clear whether the
> audio was at usable levels on the board.
Look for a Coco 3 manual - that was factory wired for video and sound.