Backlight problems

[Ken]

Well, I guess something changed on my system and now I have a bit of a 
problem.  The backlight on my laptop seems to turn off randomly and 
refuse to turn back on.  Luckily I can work with it with the attached 
monitor.  

I've found through experimentation that I can get the backlight to turn 
back on in a couple of different ways.  If I run 

xset dpms force off

Then the screen will blank.  If I hit a key then both my external monitor 
and my laptop turn back on. 

If I run 

xset dpms force standby 

I have the same experience. 

Now, the command, 

xset dpms force on

does absolutely nothing. 

So this looks like some kind of a software problem.  Something on my 
system is deciding that it is time to turn off the backlight.  How do I 
determine what it is?  Is there a way I can force the system to ignore 
these requests?  

Thanks,

-- 
Ken <ktxl45 at gmail.com>