Magic smoke today-oooooo

[Doug-in-the-woods]

had one SSR that decided it didn't want the resistor going from the opticoupler to the triac.
turned on a particular channel and oh aw SMOKE!!
turned off no smoke
turned on and the resistor started to glow on one end-small flare like weling then poof- no smoke.
the resistor gave its life for my display
WHY??
not going to worry until after Christmas and take down the display.

[P. Short]

My guess is that there was a bad connection on MT2 of the triac and the full current of the load went through the resistor instead of the triac. Or it could be a bad triac.

--

Phil