Re: [mythtv-users] No signal on TV with Audio Authority

[Cory Papenfuss]

	The only signal you *need* to look at is the Y (green) out of the 
transcoder.  That's the one with sync and the B&W component of the video. 
What you should see is a fairly small signal (0.7v for the video IIRC). 
The sync should be *very* obvious.  Basically little one-cycle chunks of 
square waves with the video voltage in between.  If the screen is black, 
it'll be around zero.  A very crude representation (with unipolar sync 
like 480i is supposed to use:)

||      ||      ||      ||      ||
||_XXXX_||_XXXX_||_XXXX_||_XXXX_||
	The XXXX would be the arbitrary video data.  In fact, now that I 
think about it, you can even hook up a composite signal to the Y input of 
a component TV.  It should sync and have a B&W signal, complete with some 
weird artifacts from the color signal that's there too.  Put the composite 
(or component Y from a DVD player) on the 'scope to see what it should 
look like.

	Sounds to me that if you're sure you're getting 7VDC out of all 
inputs, it's hosed.  Probably an easy fix inside, though... :)

-Cory
On Thu, 5 May 2005, Mitko Haralanov wrote:
        I finally had a chance to hook up the Audio Authority to a
oscilloscope and check what I am seeing.
        I am not a video signal expert so I am sharing my results here
in case someone can shed some light on whether I was doing anything
wrong.
        For the test, I connected the AA box to a Windows PC, which was
running at 800x600 75 Hz refresh rate. On the Audio Authority FAQ I
read that the 9A60 does not change the signal at all. It just passes the
horizontal and vertical sync timings and pixel content to the output.
So, even though, this might not be a HDTV-understandable signal, I
would expect that the oscilloscope would see it (on at least one of
the three outputs).
        Well, the results are that there is a voltage coming out of the
component jacks (it appears to be something in the order of 7V), there
is absolutely no modulation, it is a flat voltage and that's it.
        What did I do wrong when measuring the output? I don't think, I
should be seeing a flat voltage, right?
--
Mitko Haralanov
voidtrance at comcast dot net
http://voidtrance.home.comcast.net
==========================================

*************************************************************************
* Cory Papenfuss                                                        *
* Electrical Engineering candidate Ph.D. graduate student               *
* Virginia Polytechnic Institute and State University                   *
*************************************************************************
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