HDTV’s DAM pops Energy Star’s bubble

Feb 7, 2009
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DeviceGuru recently reported on a reader’s so-called “Energy Star compliant” Sony HDTV that consumed 150 times its advertised standby power spec. After communicating with both Sony and the EPA, the reader eventually managed to put his insomniatic TV to rest. Here’s how.

Martin Hellman writes…

I thought your readers would be interested in hearing how the Saga of my Sony TV’s power-sucking “sleep mode” ended. As you’ll remember, this is a Sony 37-inch LCD (model KDL37XBR6), bought last November and specified to draw less than 0.1 watts in sleep mode, whereas my power meter showed it drawing 20 watts 75 percent of the time it should be sleeping, for an average of 15 watts — 150 times the stated value.

DAMed if you do, DAMed if you don’t

When I last wrote to you, I suspected that the problem was with the TV guide feature. Some sleuthing had shown that the EPA exempts “Download Acquisition Mode” (DAM) from sleep mode and, based on my power measurements, I guessed that the TV was in DAM 75 percent of the time that the TV was “off.”

Worse, there was no documentation in the manual on how to turn off the TV guide so that I could determine whether this was the source of the problem. If it was, I’d leave the guide off since it wasn’t that important to me. After several back-and-forth emails with Sony and the EPA, I learned how to turn off the guide and have confirmed that it was the problem. Now, my power meter is happily reading 0 watts all the time the TV is off.

Disabling the DAM, step-by-step

If anyone else has a similar TV, here are the directions for turning off the guide:

  • Reset the TV: With the TV on, hold the UP arrow on the remote and press the power button on the TV (not the remote!). You will lose channel information, etc and have to re-run Auto tuning if you want that feature.
    • During the Initial Setup, you will be prompted (not asked, which is part of the problem) to set up the program guide. Choose DON’T REMIND ME AGAIN.
      • About 30 seconds after the TV is turned off, it will now draw less than 0.1 watts, as specified.

      A note of hope

      The EPA was not happy to learn that the DAM exception was consuming so much of the OFF time. They had understandably expected that such a small amount of data would not take long to download and told me they will be considering this problem in their next update to the Energy Star requirements.

      For those who want to make similar measurements, the Kill-a-Watt P4400 is a low cost (currently $23 on Amazon) unit and Brand Electronics sells more capable — and expensive — power meters.



      As noted in our prior coverage of this sort of problem, developers of next-generation, “smart,” consumer products seriously need to reconsider their power management strategies.


      Want to contact the Energy Star program? You can email them at this address.




      [About Martin Hellman -- Martin Hellman is renowned for his invention, with Whitfield Diffie and Ralph Merkle, of public key cryptography. In addition to many other uses, this technology forms the basis for secure transactions on the Internet. Hellman's latest project, Defusing the Nuclear Threat, has been endorsed by a number of prominent individuals including two Nobel Laureates.]



      PLEASE COMMENT BELOW

      2 Responses to “HDTV’s DAM pops Energy Star’s bubble”

      1. Bill Julyan says:

        Thanks. My new 46XBR9 was making an annoying clicking noise (sounded like power on/off) at night when the TV was turned off. I’ve followed your procedure for disabling DAM and I think it has stopped.

      2. Kamal says:

        Thanks for the information. I have a 52XBR6 and was wondering what was going on when i used to hear this click sound when i turn off the TV in the night. I tried your procedure disabling DAM , my initial setup screen comes with YES/NO option i do not see a Choose DON’T REMIND ME AGAIN option at all. Is this available on all models?