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[JeffVolp]

My CM 15 runs fast for this same reason, and I will eventually get in and filter the optical coupler output which provides the 60 Hz signal to the CY7C63723 chip. 

Something to consider is that any simple filter that eliminates noise will also shift the zero crossing, which is used to time transmissions and the X10 sample window.  Too much delay and you may have trouble sending and receiving X10 commands.

Jeff

[Brian H]

GeorgeM; I am not that surprised the reccommended parts where missing in the clocks.

Study the CM15A schematics and you will also notice none of the chips have a .1uf bypass cap on them. That are what would be called standard practice for digital designs. We had an electronics engineer report that after adding four .1uf caps to his CM15A it was much more stable. He added one on VCC to VSS for U1 and U2. Also across C11 and C12. Not sure if he also used on on C2.

My early revision CM15As don't have the caps. I don't know if on later ones they maybe soldered on the back of the board.

[dave w]

IT'S THE DAMN BEAN COUNTERS AGAIN!!!

[JeffVolp]

IT'S THE DAMN BEAN COUNTERS AGAIN!!!

Maybe...  While they cost me about a dime each, they probably only cost one or two cents each at the quantities they would buy.  And you really only need one high frequency bypass on a small low-current PCB like that.  Of course it also costs something to install onto the PCB, but we aren't talking big savings by leaving it out.

Jeff

[dave w]

IT'S THE DAMN BEAN COUNTERS AGAIN!!!

Maybe...  While they cost me about a dime each, they probably only cost one or two cents each at the quantities they would buy.  And you really only need one high frequency bypass on a small low-current PCB like that.  Of course it also costs something to install onto the PCB, but we aren't talking big savings by leaving it out.

Jeff

I think it is the X10 mindset. I have seen them take out caps before. "If it will work with out it...leave it out".

[Brian H]

dave w; If you have ever looked at some of the X10 schematics on the FCC site?
Components with a * are not installed.

[GeorgeM]

Now, here is an interesting development.  After I retuned the output frequency on my CM15A, I plugged it in at a location I had not previously used, but which is more convenient to the computer.  It appears that it is no longer gaining time.  I have no explanation, and presently have too many other hot projects (repairs) to pursue an investigation, but wanted to report the new condition.  Previously, I would have had to reset the CM15A time at least once by now, but it continues to stay synchronized.  I'll check back in if I ever have time to run the tests to determine what has happened.  I think this outlet shares a circuit which may have equipment with serious line filters installed, but until I have the time to chase it out, I can't be sure.