Metspitzer said:
My laptop refuses to display on the TV using the S Video cable. it
does display HDMI on my living room HDTV. It will also send a signal
to an external flat panel.
Is there a cable that will connect to a USB port and carry a video
and/or sound to the inputs on an older TV.
My bedroom TV has no HDMI connections.
I'm not aware of a USB to S-Video.
There is USB to VGA. Then, you can use various scan converter products
to go from VGA to S-Video or Composite. It would be an expensive,
and not very satisfying solution, because scan converters can look
a bit washed out (too bright).
There is no particular reason technically, that they couldn't do
a USB to S-video. I expect the companies making this stuff, don't
see a market for it.
This is an example of a modern USB to VGA/DVI. This one uses
compression on the USB cable, to be able to move more data.
http://www.pcper.com/article.php?type=expert&aid=555&pid=2
It uses a chip from DisplayLink, which handles the conversion.
http://www.pcper.com/images/reviews/555/board.jpg
This is an example of a scan converter. Notice the comments
are not too good. Newegg has a number of other VGA to S-video
or composite converters, but the reviews are no better.
http://www.newegg.com/Product/ProductReview.aspx?Item=N82E16814100010
It would be better to continue to work on the laptop problem.
*******
I've tested some of my video cards here, using "fake" connectors
to fool the video card. For VGA, to make it look like a monitor
is present, you buy a 15 pin VGA connector, and wire a 75 ohm
resistor from Red to Red_Ground, a 75 ohm resistor from Blue to Blue_Ground,
and a 75 ohm resistor from Green to Green_Ground. When I plug that in,
the Display control panel thinks a VGA monitor is present. My solution
does not give EDID data, so there is still an issue if I want to
go higher than 1280x1024. But I can clone or extend the desktop
to the fake connector if I want.
For composite video, I use a S-video to composite adapter bullet, and then
I connect 75 ohms from the center pin of the composite RCA (Cinch)
connector to the ground. When that is plugged into the video card, the
Display control panel thinks a TV is present. You could do a similar thing,
without the S-video to Composite, by connecting 75 ohms from Luminance to Ground
and 75 ohms from Chrominance to Ground. Those would be the four
pins on the S-Video (Y, C, Gnd, Gnd).
If I had your laptop right now, I'd be getting out my two 75 ohm resistors,
to stuff in the holes of the mini-DIN, and see if the Display control
panel recognizes a new device is present. Wirewound or big-ass resistors
should not be used for this purpose - the small leaded 1/8th watt or
1/4 watt resistors are good for the job, as they're carbon composition,
and flat to about 1GHz or so. There shouldn't be any significant ringing
or reflections from the carbon composition resistor.
You used to be able to get these for $0.05 each, when I was younger.
The prices here seem to be worse than Radio Shack.
http://www.surplussales.com/Resistors/CarbonComp/Res-CarbonComp_7.htm
In the picture here, one resistor goes from pin 2 to pin 4. The other
resistor goes from pin 1 to pin 3.
http://en.wikipedia.org/wiki/S-Video
Our good friends at Radio Shack, don't appear to offer 75 ohm resistors
right now. But don't despair, as they have 150 ohm ones, You can connect
two 150 ohm resistors in parallel, to make a 75 ohm resistor. The DIN connector
for S-video, would look like this for your experiment where no TV is
present. If you're careful, you can poke the pairs of resistors, right
into the socket on the laptop. Being careful not to short the resistor
legs to any other metal on the laptop while doing so. With this pack
of five resistors, you'll have one left over.
http://www.radioshack.com/product/index.jsp?productId=2994582
+------+-----------X X-----------+------+ An
| | | | S-Video
150 150 150 150 Dummy
ohm ohm ohm ohm Load
| | | | For
+------+---------X X---------+------+ Detection
Testing
With that stuff in place, the Display control panel should be showing
a TV set is now present.
Some "real" TV sets, have an electrical load that doesn't get
close enough to 75 ohms, for the GPU to detect something is
present. In the past, the Display control panel used to have
a "Force detection" option, to enable TV output. That is something
else you can look for, before spending any more money on this
project.
I have actually tested a four monitor setup, with two video cards,
where three monitors were "fakes" and one monitor was real. By doing
a desktop PrintScreen, I was able to capture a picture of the
extended desktop, to prove it all worked. You cannot look at the
output on a "fake" connector, but by looking at the Display
control panel, you can see the computer is driving out a signal.
Paul
