[mythtv-users] DPMS and televisions; some useful ideas and a question

Shawn Willden shawn-myth at willden.org
Tue Mar 8 17:55:51 UTC 2005

I have kids and a brand-new 50" DLP HDTV, which has a bulb that will 
eventually burn out.  In case the conflict there isn't obvious, the kids 
have a tendency to leave the TV on, wasting electricity and reducing the 
bulf lifespan.  I was looking for ways to fix this and figured out some 
things that may be useful to others.

I also have a question about what settings are "optimal" for preserving 
the life of my projector bulb.

If your TV, like mine, has an automatic power-down feature when there is 
no input signal for a time (mine shuts down after 15 minutes with no 
signal), then you can effectively use DPMS "suspend" mode to shut off 
your TV automatically.

There's no problem with losing the picture during video playback even 
with fairly aggressive DPMS settings, because mplayer disables DPMS 
while it's running and xine sends fake X events every few seconds to 
simulate user activity.  I would suppose the Myth live TV player does 
something similar (I don't have any TV signal; we just watch movies).

To get my TV to shut off, I use a five-minute inactivity timeout for 
DPMS "suspend" mode.  Something like:

    xset dpms 240 280 300

But that will only work if xine is not currently running.  So, I added 
"-pq" to the command line options to xine, which causes it to exit when 
the video ends.  20 minutes later, assuming no user activity, the TV 
will turn off.

Maybe this is really obvious to everyone else here, but I found it quite 
nice that I could get the TV to turn off automatically.

What I'm unsure about is what is really best for the life of the bulb.  
Clearly electricity usage is optimized by shutting off as quickly as 
practically possible, but I know that many electrical components suffer 
more damage due to the heating and cooling associated with on/off cycles 
than they do by simply being left on all the time.  Does anyone have any 
idea what usage pattern maximizes the lifetime of the bulbs in 
projectors and projection TVs?



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