SC1200A XM19A Supply Off Frequency

[Brian H]

While doing my SC1200A XTB-IIR tests for a separate post.

I found the XM19A power line frequency as measured by my XTBM to be between 124-125KHz 5.71 volts. On an XPPF isolated power feed.
The 49-1000P supply from the Radio Shack 49-1000 kit measured 119-120KHz with a 5.15 volt output.

Yes the RS supply works fine on the SC1200A.
The power line transmitter is part of the wall wart supply not the console itself.

[JeffVolp]

I found the XM19A power line frequency as measured by my XTBM to be between 124-125KHz 5.71

That does not suprise me.  Several years ago I found one of my Maxi Controllers would not work through the XTB-IIR X10 Boost input.  I could find nothing wrong with the XTB-IIR, but I did discover the Maxi Controller transmit frequency was 130KHz.  It was an old "boxy" Sears unit, and it was easily re-tuned by adjusting a slug in one of the coils.

Jeff

[Brian H]

I may play around with it.
As far as I can tell. It is a power line transmit only.
Four wires to the console. Probably power; common; transmit key and maybe zero crossing if the console is doing all the work.

[Brian H]

I opened the power supply and re-tuned it much closer to 120KHz from the 124-125KHz it was reading on my XTBM.

[dave w]

I opened the power supply and re-tuned it much closer to 120KHz from the 124-125KHz it was reading on my XTBM.

Is the power supply a "crack apart" or a "melt it with a solder iron, cut it with a Dremel" case?
X10 should be ashamed. They appearently have no quality control anymore.

[Brian H]

Two screws hold the back lower edge and the top two snap into a slot.
AC input of the power transformer is the two prongs sticking through the back. They are part of the transformer itself.
Take the back off and the transformer can slip out of it. Sandwitch fit between the back cover and the front.

The AC also has two wires to the PCB so it can detect the zero crossing and have a transmit connection back to the power lines. They are soldered to a tab on each AC input pin of the transformer assembly.
Also three secondary wires from the transformer to the PCB.

Radio Shack version of the supply.

[vlong]

since you  already open one does it has tuner CKT to addjust Frequency?

[Brian H]

Yes. Two small tuneable transformers.
One is the oscillator tuning. For the 120KHz frequency.
The other one is the coupling transformer in the output transistor circuit to the power line.

I have used my XTBM to test other X10 devices.
I have found a CM15A running at almost 124KHz also. Others in the 121KHz to 122KHz range.