Re: bizarre x-10 dead zone

[nobody@xxxxxxxxxxxx (Dave Houston)]

J Miller <reply@here> wrote:

>David White wrote:
>> Mark Chambers wrote:
>>> Hi All,
>>>
>>> Here's one that really has me scratching my head.
>>>
>>> Recently I lost the ability to control two incandescent lamps
>>> connected to an LM465 lamp module.  I replaced the module but the
>>> problem remained.  I tested both modules at my bench and found that
>>> they worked fine.  I tried an AM466 appliance module but it too would
>>> not respond.  I got frustrated an installed an RR501 module which
>>> works because it receives the RF control signal via its antenna, not
>>> the AC line.  I figured my passive coupler had failed and that it was
>>> time to replace it.
>>> I replaced the passive coupler with an XPCR active coupler and sure
>>> enough I can control the RR501 from mini-controllers or my CP290.  I
>>> replaced the RR501 with an AM466 but found that I lost the ability to
>>> control it.  Replaced the appliance module with a lamp module and
>>> control is back.  So a lamp module works, the RR501 quasi-appliance
>>> module works, but appliance modules won't work.
>>>
>>> Now it gets bizarre.  The problem only occurs in the last two outlets
>>> on the circuit.  In any other outlet on the circuit, any of the
>>> modules can receive X-10 signals and work as they should.  I don't
>>> actually know where the affected outlets are on the circuit and don't
>>> have access to the wiring to confirm their location.  Any ideas as to
>>> why only AM466 appliance modules are affected and only in these two
>>> outlets?  Note, there are no CFL bulbs involved.
>>>
>>> Thanks, Mark
>>
>> Mark,
>>
>> I had something similar recently. Let me ask, have you plugged-in
>> anything new on that circuit? In my case, it was my new LCD TV. I
>> purchased a filter unit that sits between the TV and the wall plug and
>> all was well once again. Your mileage may vary but it was great for me.
>>
>> David
>
>I was going to say that this sounds like a "signal sucker".  Something
>(probably something new) is clobbering the signal.  Could be a
>combination though, so start unplugging stuff and see if it starts working.

It might be a new signal sink or it might be a new noise source. A lot of
switch mode power supplies (e.g. those in CFLs) put high frequency noise on
the powerline while those that filter this out tend to also attenuate X-10.
Anything between 75-220kHz can cause problems for most X-10 receivers,
making them see a constant stream of 1-bits for each half-cycle,  although
the exact frequency range varies from model to model. A filter will usually
solve both problems once the culprit is identified.