Re: CM11A hangup: Any better products?

[nobody@xxxxxxxxxxxx (Dave Houston)]

There's a schematic of a lamp module at...

     http://www.edcheung.com/automa/lm465.gif

Could you use it to explain your procedure?

BTW, there is a schematic of the first version of the SmartHome 1132
(mentioned earlier in this thread) available at...

     http://home.pacbell.net/lgalvin/pwrlinc.gif

I suspect the X-10 circuitry is still the same on the latest versions.

Joerg <notthisjoergsch@xxxxxxxxxxxxxxxxxxxxx> wrote:

>Hello Dave,
>
>>>What I found with X-10 modules a lot was that their resonant circuit was
>>>quite far out of tune. That made a huge difference in some. The
>>>receivers were ok (not great) but they were listening on the wrong
>>>frequency until adjustment. Since it's an AM protocol a strong signal
>>>will still get through.
>>
>> I'm curious how you determined that the modules were mistuned.
>
>I became suspicious when I found that a module didn't work reliably in
>an outlet and another module of the same brand (they actually came with
>the same shipment) worked every single time in the same outlet. So, I
>got a schematic from the web and opened both.
>
>CAREFUL: You have to be extremely careful and know what you are doing
>since the circuitry in there is on live mains voltage, including the
>signal processing part. Do not touch anything while the module is
>plugged in. I used a power strip to avoid having to directly plug in and
>out disassembled modules.
>
>Even though the US modules are polarity keyed all it takes is a miswired
>outlet and there can be the full mains voltage on what you thought
>should be ground in the module. In Europe it is worse in some countries
>because many of their mains plugs and outlets are not polarity keyed.
>
>Then I made myself a Hi-Z toroid pickup circuit for the oscilloscope
>which I could solder on while the module was unplugged. This would also
>protect the oscilloscope. I looked at the amplitudes on the other side
>of the tuned circuit while sending lots of bogus codes with a wireless
>remote via the transceiver. The flakey module showed only half the
>amplitude of a "good" module. That was a whopping 6dB less sensitivity
>which is a lot for X-10. It was simply listening on the wrong frequency.
>Now I took a good communications receiver and verified the frequency of
>the transceiver, to make sure I wouldn't adjust all the modules to the
>wrong baseline frequency. It was pretty much right on.
>
>After tuning them all with a fully isolated alignment driver (from a
>Bernstein kit) they all performed fine. There was no longer a difference
>in reliability between modules on this "far away" outlet. I did not do
>the in-wall dimmer modules because they worked ok and I didn't want to
>go through the hassle of taking them all out again.
>
>> I've looked at the frequency of several X-10 transmitters and found all to
>> be at 120kHz.
>
>I found the transceiver and the CM11A to be pretty close to 120kHz but
>not all of the receivers.
>
>Again, for anyone reading here: This is just a recollection of what I
>did, NOT ADVICE. Tampering with the modules can be dangerous.
>
>Regards, Joerg
>
>http://www.analogconsultants.com