Re: X10 TM751 and "runaway" dims???

[nobody@xxxxxxxxxxxx (Dave Houston)]

I've forgotten who it was who first posted that he could cure his TM751 by
aligning the antenna at a right angle to the 120V wiring in the wall behind
the outlet.

Take a powerstrip with a few things plugged into it including a lamp module
and TM751.

Align the antenna with the power cords.

Send a Dim.

Play with the antenna orientation and length.

I found that I could induce and stop the endless dims at will with any of
about 6 TM751s I tried.

If RF is present at certain times after the initial signal, the TM751 and
RR501 will send another dim. It could be that inductive coupling of the
120kHz to the antenna is enough to trigger the oscillator in the
superregenerative receiver circuit even though there's a big difference in
frequency.

Charles Sullivan <cwsulliv@xxxxxxxxxxxx> wrote:

>For some installations, sending any X10 RF dim signal to a
>TM751 transceiver results in a runaway dim situation where
>the lamp becomes totally dimmed.  And it may be necessary
>to unplug the TM751 from AC socket to stop it from sending the
>repeated PLC dims.
>
>I've been led to believe that there is some sort of RF feedback
>which causes this problem.  Can anyone explain the mechanism
>involved?
>
>Regards,
>Charles Sullivan