Closed richard-sim closed 3 years ago
This eevBlog Forium thread discussion goes into a lot of details about the C245 Tip. And is the best source of information I have found on the subject. It's probably worth the time to read the comments over there.
There's an even better EEVblog forum post where someone has reverse engineered the entire circuit of a JBC CD-2BC: https://www.eevblog.com/forum/testgear/jbc-soldering-station-cd-2bc-complete-schematic-analysis/
To correlate the terminology from the schematic and the image I've included below:
If you look at that the top of page 2 of the schematic from that thread, it's clear that C245 (and C210 for that matter - but they're a different beast in other ways) cartridges will have their heaters powered through the COM and LOAD pins only - never the TC.
Hey, I was looking over your schematic and it looks like you're powering the heater through the TC as they're connected in series in the cartridge with the 3 wires being either end and the common point between them. Going by the Bottom schematic, C245_JUNC is the common connection between the heater and the TC, so the heater should be powered by J3.1 (V+/heater) and J3.3 (C245_JUNC/common), and the TC sensed between J3.4 (TC) and J3.3 (C245_JUNC/common).