^thanks a bunch, guys.
I finally got my first T12 tip in the mail, yesterday, from a US seller off Amazon. It came in a plain faraday cage metallized bag with no "hakko" stamped all over it, like my T18 tips come, and the chrome plating doesn't look particularly smooth. I am assuming it is a fake. It was under a tenner.
I measure 8.3 ohms across the heater, which is surprising to me. I heard it was supposed to be 2ish ohms. Does not the heater increase in resistance as it heats up? Well I will have to do some testing on it, at some point. The 888D ceramic heater has 3.3ish ohms, for instance, when it is at room temp, but it reaches about 8.8 ohms at 350C. If the T12 tip does the same thing with the same coefficient, it is only running at 20W, lol.
Anyway, I hit my first hump in my 888 to 951 conversion. After switching the triac to the hot side, even when the triac is off I get a +-3V ripple out of it. I can't see getting a meaningful adc read of the TC out of this nonsense. I wonder if this is why sparkybg's controller rectifies the AC and switches unfiltered DC with MOSFET (and also uses zero detection to time the reads at 120Hz when available power is minimal).
I guess I shall have to see if I have a FET up to the task and then podge up a full wave rectifier. Pity, cuz I just finished populating and wiring up a dev board based on the Triac switching model. I guess I got the cart in front of the horse on this one.