Why is my controller outlet-dependant?

[Brian H]

Computers are never 100% Off if plugged in.
Their power supplies are always running. The On/Off button does not physically disconnect the AC to the power supply. As it is always running for the remote power button to turn it on and off.
That is why you have to unplug any suspected device as most modern electronics are running in a power saving mode not Off.

[JeffVolp]

In my case, the computer I filtered (upstairs) does not have a UPS.  It is (was) plugged directly into the outlet.  Unfathomably, it made no difference if the computer was turned on or not, the module behavior was the same.

The two computer power supplies that I took apart had capacitors from hot and neutral of the AC input connector to chassis ground.  This is to meet the FCC regulation on conducted radiation.  Those capacitors also present a serious load to any X10 signals on that circuit when the computer is plugged in, regardless of whether it is on or off.

Jeff

[bkenobi]

You should not have to have an X10 filter on a computer. If it is behind an UPS and the UPS AC input is on a filter.

I have a filter for all UPS's but I don't also put a filter between the UPS and the PC.  If the PC is without a UPS, I'd filter it.  I've added more UPS's so basically all electronics are behind one (computers, TV, HA setup, etc).