FC3: Garbage on text consoles

[Frank]

I'm running FC3 and have all the latest updates installed.  System boots 
nicely into X and everything works except that if I change to one of the 
text consoles (alt-F1) the screen is filled with gibberish with 
different attributes (colours, blinking, reverse, etc.).  The display is 
identical on all consoles.

This worked fine a few days ago.  Since then I have installed FC3 
updates, and attempted to install a Matrox video driver.  It told me 
that my kernel is unsupported, so I am still running the generic VESA 
driver.  Not sure that any of that should matter on a text console...

What could cause this?

Frank.