Lubrication of the belt should be easy. And if you've had it for 10 years without lubricating it once or twice a year, that's probably what's burning. But it could also be a cable. Did you unplug it? Don't leave it plugged in case it bursts on fire.

I feel like I've read that what lube is used varies by treadmill & the wrong type can also cause problems. DH seems to think it was friction related.

Yeah, and without the lubrication it can cause friction. Most TMs now use non-silicone based. I don't think it hurts at this point putting some under the belt and see if it works. You think the TM is shot so worth a try in case it's that simple.

I guess. I've wanted a new treadmill for quite a while now and being off next week it means I have time to go look and for us to take the old one to the dump. This one is really narrow, so almost anything will be an improvement.

Oh, yeah, I would be tripping there left and right. Yeah, don't tell your husband to lubricate it. Buy a new one. 

I've gotten used to it over the years, but I know it's not the ideal treadmill.  I'd be screwed if I ever had to quickly get on the side rails.