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[pomonabill221]

  I know this is a BIG BIG BIG issue with X10 signal strength, and signal suckers. 
  I have found that ONE of the BIGGEST suckers are SMP supplies. (switch mode power supplies).
  These are found on laptop / desktops, cell phone chargers, some battery chargers, in TV / stereo / VCR (yes they're still around) / DVD players, printers, monitors, on and on!!!!
  The culprit is the power supply's line input filter.  It is usually a pi filter made of a cap/balanced choke/cap (or just the first cap and choke) network.
  The cap is usually anywhere between .068 to .22 uf... DOES THIS VALUE RING A BELL??
  This is the SAME value that "phase" (or correctly LINE) coupling networks use to couple the 120Khz signal from line to line!!!
  When the cap is across the line to neutral, WHALLA!!!  there goes the signal, being ATTENUATED (or shorted).
  The FIRST thing I do (although not for the faint of heart  ), is to remove the first cap.
  Sometimes that means cracking open the power supply adaptor case, as it is usually glued together.
  For instance, my TV (a Princeton TV/computer monitor/RGB/Svideo) takes a 145mV signal to 0!!!!!! as measured with my XTBM.... sooo I removed the cap and no more signal loss.
  I have also done this on all my computer monitors, laptop power supplies and SMP battery chargers.
  I know, I know.... this is BAD advice as it voids warranties AND the caps are there to keep radiated SMP noise from coming OUT of the supply, but I have yet to see noise FROM these supplies.
  I also have a HUGE noise generator uwave oven.  It is a panasonic 'Inverter".  Guess what???
  THE "INVERTER" IS A HIGH POWER SMP that runs the magnetron, running at.... 35Khz with TONS of harmonics that CREAM X10 signals.
  Nothing works when the over is on!!!!  SOOOO.... I use a Sprauge rf line filter, and according to my XTBM, the noise is around 10-20 mv where it used to be 150-170 mv on the same plug, at zero crossing.
  NOT perfect but X10 now works when the oven is running!!!
  I mention all of the above to maybe trigger someone else's thinking about what they have in their house that maybe affecting X10, and what could be done as an alternate.
  I AM NOT PROMOTING OPENING UP YOUR POWER SUPPLIES / TV'S TO REMOVE THE CAPS!!!  THIS WILL VOID WARRANTIES AND IF NOT DONE PROPERLY, COULD DAMAGE THE INNARDS AS WELL, SO BE CAREFUL!!!

[JeffVolp]

Yes, that across line capacitor is what causes "signal suckers".  However, there is something else to consider.  Manufacturers usually don't add components that are not required.  That capacitor is in there so it meets the FCC spec for conducted radiation.  If they only added an inductor in series with the AC input, there would be no problem.  But, that would cost a few cents more.

Jeff

[dave w]

FWIW
Years ago I hacked X10 lamp modules for video studio lighting remote control. Obviously the chokes in the Lamp Modules would not handle the load of 5kW Klieg lights. I kept all the chokes I stripped out of the modified Lamp Modules. Twenty years later I am using those chokes.

A few weeks ago I purchsed a night light / rechargable flashlight / power failure light which turned out to have a very noisy switching power supply which killed X10 in about half the house. The emergency light plug orientation did not lend itself to using a plug-in filter. There was extra room in the emergency light housing so I dug out one of the old chokes and put it in the hot line between plug prong and PC board of the emergency light. Fixed the problem.

The lesson is: next time a bulb blows and shorts the triac in a Lamp Module and you are not in the mood to replace the triac, cut the choke out of the module before tossing it. It will come in handy later.

[Brian H]

Some CFLs I have disassembled have a AC rated cap across the AC input. 
Though others I have seen still have the cap but for the few extra cents. Have a small choke from the assembly to the center pin of the bulbs connector.

Don't forget we now see things like electronically controlled washing machines and refrigerators as problems. Most likely a AC cap again.

[Noam]

... Manufacturers usually don't add components that are not required...

And, in the case of X10, they sometimes leave out components that SHOULD be required ;-)

[pomonabill221]

Yes I do realize that the input cap is there for conducted radiation and for FCC compliance (I knew my comments would cause a reaction, and I realize that that is what the cap is for).
  Even some devices WITH the input cap STILL make ALOT of switching noise (elsewhere on these forums, a particular cell phone charger has been characterize in great detail regarding conducted noise).
  I also have read that the choke used in the lamp modules is a GREAT thing to use as a noise block, but have yet to use one myself.  Just waiting to blow a lamp module and be too lazy to replace the triac! 
  I always look at the line after cap removal to see if the SMPS radiates any noise as this would defeat the purpose of removing the cap in the first place!
  I used to use my scope, but I use my XTBM as well just to verify noise problems (thanks JeffV!)
  I second that Noam!!! 

[Noam]

Is all this being done to avoid adding plug-in filters? Would plug-in filters accomplish the same thing?

[Jeff M]

I just noticed that when my bathroom light (fixture with two CFL bulbs) is on, then one of my applicance modules does not respond to ON/OFF commands.  Dave, you mentioned a choke in series with offending power supplies solved some of your problems.  Since I don't have a stocked junk box, is there a specific part number for a choke that can be purchased?  I assume that this can be put in series with the hot line of the offending light fixture.

[JeffVolp]

A Leviton 6287 filter placed in-line between the switch and the light fixtures should solve the problem.  That filter is fairly small, and may fit either behind the switch or into the fixture electrical box.  Unfortunately, the 6287 is expensive (about $25).

Jeff

[Jeff M]

Thanks for the info on the filter.  I was hoping that there was something inexpensive from a parts supplier like DigiKey, that only cost a few bucks.

[JeffVolp]

Thanks for the info on the filter.  I was hoping that there was something inexpensive from a parts supplier like DigiKey, that only cost a few bucks.

The couple buck inductor fix from Digikey is suitable for a table lamp or some other "plug-in" device.  I added them to two of my computer power supplies.  I don't recommend that for in-wall house wiring.  While it will probably work fine, I doubt that an inspector would approve.

Jeff

[Jeff M]

Can you recommend a part number for a specific inductor that would work?

[Jeff M]

I found these link to schematics for a couple of the Leviton filters:

http://idobartana.com/hakb/6287_Schematic_vA.pdf

http://idobartana.com/hakb/6288_Schematic_vA.pdf

Here is an interesting article that I found about X-10 and CFL bulbs.  It also recommends a couple of inexpensive chokes:

http://jvde.us/x10/x10_cfls.htm

[Brian H]

As Jeff's tutorial indicates. Watch the current rating of any choke coil you pick. So the load is not too much for it.

Schematic of the Smarthome 1626-10 ten amp FilterLinc. IMHO the discontinued 1626 five amp was the same except for the five amp fuse in it.
http://home.comcast.net/~gafield/family/gary/electronics/X10_Filter.pdf

[pomonabill221]

It is strange that the leviton 6287 filters spec. a 1 uF for C3, and the X10 specs. a 2.2uF, even though the other caps/chokes are the same, except 7uH instead of 8uH???  hhmmm...
I built the Leviton 6287 (7uH/.22uF and 1uF) and checked it on a spec analyzer, and the notch was at 130kHz, even though the slope was very steep around 120kHz, and it did work, but did reduce some of the 120kHz carrier when used with my HP printers that really sucked the signal.
  Yes, when one does not have alot of income, one tries to be creative by building and/or modifying things.
  If I had alot of funds, I would buy filters rather than modify things, or build things, but this takes away from the satisfaction of finding solutions to problems, and researching fixes for problems.
  This is something that I have always done for myself, but wanted to share some of my ideas and experiences.
  Reverse  engineering is something that I have always done, and enjoy to do as well.
  I think in the future, if I have an "alternate" idea about something, I will just keep my "mouth" closed.  This would keep sanity and not create a possible problem for others.