HDMI Backfeeding

[reaper57]

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?

[reaper57]

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.

[diif]

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.

[japlytic]

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.

[TechGeek]

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.

Okay, they REALLY need to adopt 3-phase power, like here in the US.

[tom66]

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...