Hmmm different behavior tonight, even before I did anything.
The pulse was only after plugging in the string. But if I un-plugged and plugged it was consistent. Lat night it was doing it while plugged in.
Swap 485 chip, same behavior
Swap Opto, same behavior
Reviewed all solder joints OK
Swap PIC - Viola, no pulse, BUT, there is a small pinpoint of light on the LEDS, so that tells me that the triac is going??
Next question, I know we try to get units these more economical with the coops. Are there a bit more dependable triacs? Understanding that they may be more cost too. Any vendor/partnumbers?