First check the soundcard
<ol>
<li>Is your capture card plugged into your soundcard?
<li>Does the line-in on your capture card work?
    <ol>
    <li>Are you using the digital audio output of your soundcard?
    </ol>
<li>Have you turned up the volume on every channel you can think
    of to see if any of them map to the line-in?
</ol>

Then check the tuner driver
<ol>
</ol>

Then check the tvtime settings
<ol>
<li> frequency table
<li> norm
<li> bg vs dk vs i
<li> audio boost
</ol>