Trapped X10 ghost signals

["Thierry Parent" <TParent@xxxxxxxxxx>]

Just to contribute to the X10 home automation knowledge base, I discovered
two weeks ago the reason of unexpected X10 modules lighted ON.

Symptoms were :
P16 ON triggered sometimes also P1 and/or one of the two modules coded on
E10.
P16 also triggered systematically E5.
J3 ON triggered sometimes J1.

Second case was quickly fixed. The reason was a wrong setup of smarthome
2000STW module by defining the P16 as the "group scene" (secondary) address.

"sometimes" means a periodicity of 1 time each three days, but at least one
each week

All the modules are based on X10 original design, but some are true European
version (not converted), other US with a mix of appliance and lamp.

Capturing the X10 commands with a CM11 or Powerlinc USB didn't provide any
relevant information (no trace of issued commands relating to P1, E10 or J1
command)

By the fact that triggering occured only on one module of a shared address
(E10) for two distinct module, I decided to exchange the module without
improvement.

I tried with a scope to tune the defect module (tuning self to improve 120
kHz detection) without success.

There was no real logic related to the module place. Some were far away form
the distribution panel, other close and problem was not limited to one room
but always to the same module with fixed address plugged at fixed places.

Finally I discovered that the problem was a power switching supply providing
the required 5V to my wireless router located very close to the breaker box
and therefore my ACT X10 signal repeater.

I have no rational explanation, just a fact. Remove the power supply and
reliability is back. Let it on 24/24 and you will encountered false
triggering in a week. I have already installed signal filter (especially on
TV and computer plug) but, on the basis of my knowledge, filter are
adressing loosing signal strength, not false triggering.

It also seems that problem is related to the X10 original electronical
design. I didn't encountered any problem with my smarthome or ACT modules
(14 on a total of 37 globally installed).

Hope it helps

Thierry