If the tranceiver is receiving the remotes
signal and the tranceivers power line signal
is not getting to the upstairs light. You
may have a phase problem. Most homes have
split phase and about half the home is on
each phase. X10 signals have problems
getting from phase to the other phase. As a
test can you move the lamp module to another
room maybe upstairs and see if it works
there. Also sometimes turning on a 220 volt
appliance like a dryer or stove [not a 100%
test these days due to electronics in the
appliances]and see if the not responding
module then works. If it does you need a
phase coupler or coupler-repeater. Move the
module to a different outlet. I turn off my
X10 coupler/repeater and actually can move
my RR501 Tranceiver around the house and see
which circuits are on each pahse. I actually
have in my living room. Two circuits. One on
each phase. With the repeater off. Half the
room works the other doesn't. If I move the
tranceiver to the other phase the reverse
happens.
Also try unpluging things like TVs computers
etc. Then see if the range is better. If so
those devices may need an X10 filter for
noise or signal absorption.
