Converting a LM465 X10 module to 230V

The LM465 is a "lamp module". In contrast to an "appliance module" it does not have a relay, but controls a lightbulb's intensity using a triac. It can be used for lightbulbs ("incandescent loads") up to 300W, and it controls their intensity with the 22-step resolution common for X10 devices.

My module was not an original LM465, but a cheaper copy - the Philips Magnavox LMT-101. It seems to be identical to the original, but I got it for US$ 3.95 at a mail order store. I converted it using the instructions at redoak.co.uk. They also have a circuit diagram online. All photos can be enlarged by clicking on them.

This is what the module looks like in its pristine state:
 
left: original module and interior right: the module and its parts

  Since all resistors were 0.5W types already, I only had to exchange three components: The large blue capacitor, the MOV (which was a bit hard to find because it looked like one of these capacitors), and a 100 Ohm resistor.

I bought these parts at a local electronics store:

  • 250V MOV "SIOVS14K250", at 1.02 EUR
  • 0.33F, 400V polyester capacitor, at 0.66 EUR
  • 100 Ohm, 1W resistor, at 0.20 EUR
Needless to say that you can get these much cheaper if you order in quantity.

Here's a detail photo of each replacement I made. Of course, I first removed all the old parts and then put in the new ones.

The capacitor:

 
left: 0.68/250V capacitor (old) right: 0.33/400V capacitor (new)

The MOV:

 
left: 120V MOV (old) right: 250V MOV (new)

The resistor:

 
left: 0.5W resistor (old) right: 1W resistor (new)

Finished!

 
left: finished module with wires (ground still to be connected) right: finished module in original case

I was quite happy with the result. It worked, it didn't get warm, and it didn't make a sound (in stark contrast to the "clack" produced by the appliance modules).

Try this at your own risk. It may not be wise to connect the module to a power strip like I did... one day someone plugs a vaccum cleaner in, and I doubt that the triac would survive that. If you intend to operate the module at 240V AC, take a look at aforementioned instructions from redoak.co.uk and think about replacing the triac by a higher-voltage type. It seems to be ok for the German utility voltage of 230V AC.


  Frederik Ramm, 2004-07-03