HDMI Backfeeding

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  • reaper57
    Badcaps Veteran
    • Sep 2014
    • 216
    • Norway

    #1

    HDMI Backfeeding

    So guys my xbox 360 has been giving me some power issues lately and weird thing that I've noticed is that if I leave the HDMI cable plugged into the console and in my monitor my power supply's standby LED would turn on. It's not as bright as when it's plugged into the wall but it's pretty visible. This is with the power supply disconnected from the wall, but plugged into the console.
    Do you think that this is normal, and could it cause my console to shutdown and display a power error?
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  • reaper57
    Badcaps Veteran
    • Sep 2014
    • 216
    • Norway

    #2
    Re: HDMI Backfeeding

    Btw, here in Norway they use the two-phase system, and most power sockets are ungrounded. So basically pretty much everything that has a metal chassis has a constant current running over all the exposed metal parts. Escalators even zap you sometimes.
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    • diif
      Badcaps Legend
      • Feb 2014
      • 6978
      • England

      #3
      Re: HDMI Backfeeding

      Have you checked the voltages coming out of the adapter ?
      It sounds like some sort of grounding issue with voltage passing down the HDMI cable.

      Comment

      • japlytic
        Badcaps Legend
        • Oct 2005
        • 2086
        • Australia

        #4
        Re: HDMI Backfeeding

        Ungrounded equipment can induce noise through the cables and therefore cause problems - I've read about a seminar that someone held where everyone in the room was asked to remove their footwear due to the computers crashing due to poor grounding.
        My first choice in quality Japanese electrolytics is Nippon Chemi-Con, which has been in business since 1931... the quality of electronics is dependent on the quality of the electrolytics.

        Comment

        • TechGeek
          Computer Geek
          • Jan 2015
          • 2254
          • USA

          #5
          Re: HDMI Backfeeding

          Originally posted by reaper57
          Btw, here in Norway they use the two-phase system, and most power sockets are ungrounded. So basically pretty much everything that has a metal chassis has a constant current running over all the exposed metal parts. Escalators even zap you sometimes.
          Okay, they REALLY need to adopt 3-phase power, like here in the US.
          Don't buy those $10 PSU "specials". They fail, and they have taken whole computers with them.

          My computer doubles as a space heater.

          Permanently Retired Systems:
          RIP Advantech UNO-3072LA (2008-2021) - Decommissioned and taken out of service permanently due to lack of software support for it. Not very likely to ever be recommissioned again.
          Asus Q550LF (Old main laptop, 2014-2022) - Decommissioned and stripped due to a myriad of problems, the main battery bloating being the final nail in the coffin.


          Kooky and Kool Systems
          - 1996 Power Macintosh 7200/120 + PC Compatibility Card - Under Restoration
          - 1993 Gateway 2000 80486DX/50 - Fully Operational/WIP
          - 2004 Athlon 64 Retro Gaming System - Indefinitely Parked
          - Main Workstation - Fully operational!

          sigpic

          Comment

          • tom66
            EVs Rule
            • Apr 2011
            • 32560
            • UK

            #6
            Re: HDMI Backfeeding

            HDMI by design has a 5V, 50mA supply to power EDID EEPROM. This allows the Xbox to know what monitor it is connected to. A proper design of the monitor would use an OR-ing diode to power the EDID from either the HDMI or the monitor's PSU, but never allow the HDMI source to supply the monitor; it's possible this diode is shorted, but more likely the manufacturers cheaped out on the design.

            And, umm, Europe uses 3-ph everywhere. Most of the US is single phase supply from split-leg transformer with two hots. (You only get 230V when you combine your two phase-split hot circuits.) Most houses in the UK and EU only get 1-phase supply, but the supply system is 3-ph, houses are just tied off successive phases to balance loads as equally as possible. IIRC, 3-ph is only used for distribution and industry in the US - very few houses have it...
            Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
            For service manual, schematic, boardview (board view), datasheet, cad - use our search.

            Comment

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