Well, Hah! I went searching down in that 2nd hole again, the one near the thermistor. Like I thought, the upper half of the hold isn't threaded, BUT, based on your advice, I went fishing down there is a little Allen wrench, and wouldn't you know it, it caught on something. So, sure enough, there's a little set screw down in the there, so the bottom half of the hole is threaded. Once I loosened that, the thermistor was still jammed in there pretty tight, but I was able to finally get it out. Far as I can tell, the "wire end" of the thermistor is slightly larger than the rest, and that's where it was hanging up. The replacement piece has that "wire end" flattened, so you can't even insert that, but it goes in far enough to get caught by the set screw. So far, so good.

Before I put everything back together, I'm just going to assemble it far enough so that I can reconnect the wiring to the motherboard and see if that fixes the error message I was getting.

I'm going to assume that I'll be back after I run that test, so see you then.

thanks again.

Ron