bizarre x-10 dead zone

[Mark Chambers <machambers@xxxxxxxxxxx>]

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