[Ti] Help Request for TiBook 800MHz LCD problem

[Rafe Day]

My 800MHz Titanium G4 suffered the hinge break problem that seems to plague
these machines.  A couple of days after the hinge broke, the display
developed color problems (as if the R signal was no longer received), then
spotty pixellation, and finally a blank gray screen.  Some of the wires in
the LCD cable had became severed as a result of the hinge break.  I
installed steel replacements for both hinges in an attempt to forestall a
reoccurrence and also replaced the LCD cable.

When I restarted the machine, still a blank gray screen -- though it still
drives an external monitor.  All connections appear properly seated, the
backlight is obviously working, and the computer is sending a video signal,
just not to the onboard LCD.

I am comfortable doing my own repairs, but am many years out of the
industry, so I'm at a loss as to my next step with this model.  Will this
necessitate a complete display swap or is there another possible solution?
Is it the logic board?  Am I missing something obvious?  How can I
troubleshoot?  What is my next step?

All suggestions are greatly appreciated.  :)