Modifying the Appliance module


Modifying appliance module from 110v to 220v

Credits: based on a description from Hans Aterjo. Source no longer available on web

Image of modification schematic (100k)

  1. Change C1 from 0.68uF/250V to 0.33uF/400V.  
  2. Change R1 from 100Ohm/0.5W to 220Ohm/1W.
  3. Change R2 from 330K/0.25W to 330k/0.5W (larger value also possible)
  4. Change R5 from 330k/0.25W to 330k/0.5W.
  5. Change C11 from 10nF/250V to 10nF/400V. This is the capacitor connected in parallel with a 2.2k resistor.
  6. Change the 130V MOV to a 250V MOV. If you use 240V use a 270V MOV.
  7. Add a resistor of 100Ohm/2W in series with one of the wires for the coil of the cam relay. Fix this resistor good and be sure is does not touch anything, it can become very hot.

Modifying appliance modules for momentary operation

source: newsgroup post by Dr. Ed Cheung

Image of modification schematic (100k)

Normally appliance modules turn on and stay on in response to an ON command, and off in response to an OFF command. In response to an ON command appliance modules modified as described in this section will pulse on then off twice, returning to the off position.


  1. If the module should be normally ON, turn it on before starting this modification. If it should be normally OFF, turn it off before the modification.
  2. Locate 330K resistor below the IC chip, between output pins and remove it.
  3. The module clicks twice because each X10 command is issued twice. Thus the two commands causes two on/off cycles. If you would like the module to be normally on, make sure that the module was left on before you start the mod.

Modifying appliance module to act as a high or low voltage relay
Source: Chris Russell  - email:

When used in conjunction with the appliance module mod to make it act as a momentary device, the following mod will basically turn it into a high or low voltage relay module (i.e. a High-voltage capable, yet over simplified PowerFlash module). Please feel free to clean up or edit this if you decide to post on your site.

1. Disassemble the unit.

2. Preform the modification for momentary operation as described on your website.

3. De-solder the connection from the relay COMMON input (at top near COMMON blade), snip of the lead the went to the board and cover with electrical tape to ensure that it is electrically isolated from 120V.

4. De-solder the black wire that runs from the HOT plug to the HOT blade and re-attach this to the top section of the relay near the contact pad.

5. De-solder and remove the two plug connections from the bottom of the board and attach two wires to the solder pads.

6. Reassemble the unit, running the two attached wires out the plug holes at the bottom.

This should give you a momentary SHORT across the two wires when the relay is ON, and an OPEN when the relay is OFF. This can be made normally OPEN, or NORMALLY shorted, depending on the last known state when the unit was modified for momentary operation.

This can also provide a latched path by not doing the momentary mod.


Modifying appliance modules for local control

Image of modification schematic Source: Post by S. M. Bloom

This modification is a must for appliance module turned wall-switch modules that control a non-dimming device, such as florescent light. This modification will add a local control in addition to the remote control mode.

  1. Make sure module is off, unplug it and then take cover off.
  2. Locate jumper near the "top" of the board and right beside the left side of the IC.
  3. Replace by a momentary contact push button switch.

Modifying appliance module to be in-line modules
source: Bob LaSalle

Here's a cheap way to create an inexpensive in-line appliance and lamp modules:

I found that it was relatively easy to open the cases, remove the metal power plug prongs and solder suitably heavy wires at both the POWER INPUT terminals and the POWER OUTPUT terminals.

I used a drill of approximate 1/8" diameter to create suitable exit holes from the modules. Leaving about 6" of high quality stranded wire emerging from the module cases, one can easily create very handy in-line modules at 'dirt cheap' prices, compared to the Leviton or other alternatives.

With a little epoxy resin, one can seal any extraneous openings from the original power prongs and, with just a dab, seal the new exiting wires firmly in place.


Defeating local current sensing

source: Tom Laureanno's X-10 Home Automation Webpage.


Before you start: there's a report that this mod doesn't work on the newer appliance modules  - so use this mod only for the older 486 modules. For the 6375, check this modification.

Local current sensing is the feature that automatically turns the appliance module on when the device connected to it is turned on. Its based on current sensing circuitry that senses how much current is drawn by the load. The following modification disables the current sensing circuitry:

1. Disassembled appliance module
2. Locate diode
3. Snip diode top lead



Disabling local control on the newer appliance module

  1. 6325.jpg (26911 bytes)
  2. Disassemble the module
  3. Locate the small jumper close to the large blue capacitor (see picture)
  4. Snip the jumper
  5. Reassemble


Increasing Range and Reliability
Credits: )) Sonic ((

This modification requires testing and tweaking the module while it is connected to the mains powerline. This information is provided AS-IS, for informational purposes only, with no warranty whatsoever.   It is your responsibility to know and understand common safety procedures, especially those involving electricity at potentially dangerous power levels. Proceed at your own risk.

  1. Start by reading the general alignment procedure

  2. Disassemble the module . It is O.K. to either leave the front cover (with the House and Unit code dials) in place, or remove both covers and work with a bare PCB. Attach a very short extension cord, if needed, to allow for adjustment while module is powered.
  3. Move the module to the location where it will be used. Bring along oscilloscope, isolation transformer (if needed), and previously calibrated controller of known correct frequency.
  4. Connect the controller to a separate circuit, or at least an electrically distant outlet on the same circuit, via some means of attenuating its 120kHz output (as discussed in the general alignment principles)
  5. Connect oscilloscope 10X probe to pin 1 of 78570 IC (i like to use the 33pF capacitor lead which attaches to pin 1), probe ground to circuit common (the narrower of the two A.C. prongs, i.e. “Hot”). Oscilloscope must be isolated from the A.C. powerline, since module must be directly connected for best results. Avoid touching oscilloscope while module is powered. I usually start with 10mV/div (X10=.1V/div actual), and 5Ásec sweep.
  6. Connect module directly to the A.C. line.
  7. Key controller to generate a continuous signal (Bright or Dim achieve this on most controllers so equipped).
  8. Inspect waveform. If there is clipping, reduce the amplitude of the signal from the controller until the displayed waveform is sinusoidal.
  9. Adjust module transformer for maximum 120kHz signal amplitude. This is likely to be a broad, “low-Q” peak.
  10. . Unplug/disconnect all.
  11. . Reassemble module and test.