HD Test Pattern

[greg53089]

Every now and then I stumble on a HD Test Pattern from HDnet but I see it only when there is a minute or so left.  Does anyone know when the test patterns are displayed for HDnet, HBO, or local?  (I think CBS does but I don't know when)  Also, how long are they displayed?

This way I can be ready to go into the service codes on my TV and set some of the settings (especially overscan)

Greg