Well I managed to hook up the element, but testing resulted in nothing on the meter for some reason. Using a fluke 12. Double checked I was in ac mode. Heh my luck. But yeah across both pins going into heating element, got 0.xx v. Wonder why I couldnt read that. Could my element be busted?
Well I guess I will just hook it all up flip the switch and hope nothing cooks again.
So yeah this was an early model yihua 936, my first adjustable iron, so it was really special to me in some weird way. My board is green and labeled "YH-936AV22-3". Back when I first got it it being my introduction to adjustable temp I used it for a year at least. But was using it one morning and smelled smoke, it stopped heating, led wasnt blinking. Took it apart and a few resistors were burnt. CaNt recall exactly which ones originally, but I ordered bt137 and just tried to shotgun it like an idiot. Recapped, replaced resistors, triac, normal diodes, and turned it on with board exposed, got to see the resistor turn black and smoke, took a deep breath. (Lol) I think I tried that twice, but failed to even glance at thd lm358. Still not sure what the right way to test that would be? but I had found a hindi video on the boobtube about testing lm358 with dmm. Of course I couldnt understand a word, he put meter in diode mode and he test from 4th pin + and - on 5 6 7 and 1 2 3, all had about max reading of average diode junction (0.8xx). Well the lm358 I took off on my recent look had 2.000 diode drop on each pin and no beep. So im going to guess that was the cause and I tried fixing it, failed gave up, then found it and figured to try again.
Last attempt resistors that burnt were
R9-75 ohm
R7-brown black green gold
R2-150 ohm
R1-330 ohm
So yeah what Ive put into this far exceeds its value lol, but I have nothing better to do than mess with cheap junk.
Replaced bt137 twice, those resistors twice, few diodes once, and then the lm358 a year or 2 late.
Im thankful for the attention and response from each and every one of you.
And I like the ingenuity of the idea of using leds in series to drop voltage.