Video out on Clamshell disabled

[David Crump]

Here's one for all you fellow clamshell owners out there...
My iBook: 466Mhz graphite SE, 320MB, 10GB
I quite often use the video out cable to attach to television and display iPhoto slideshows.
Recently I tried to do video out and it didn't work.  Opening Display Prefs shows that the NTSC or PAL option is not coming up.
Running 10.2.8
I thought it may have been the 10.2.8 update that did it.  Since this feature is important to me, I reinstalled Jaguar, and video out works again.  Updated to 10.2.6 and it still works.  I left it that way for a while, as I needed video out over Christmas.  I just did the updated to 10.2.8 again, and sure enough, no video out.
So...
My question is, is this a known issue?  Is there any way to fix this other than downgrading to 10.2.6 and staying there?
Thanks,
Dave.