I'm not sure, but I think that maybe I'm having a wicking problem...
The attys still get hot, i.e. if I take the cart up and push the battery, i can see the heating element get red if I hold the button down long enough. I can still 'draw' through the atty, though the draw gets harder. Just no vapor or throat hit.
For reference, I got my hardware from Rocky Mountain Vapor. I have a standard matte black battery w/blue LED, matte black attys, and the standard round poly-fill carts. I'm vaping Tasty Vapor 35% VG 24 mg nicotine/ml (Dulce de Leche, Apple Pie, Blueberry Cheesecake, and Strawberry Cheesecake). The flavor and vapor production on the juice is awesome when the attys are working properly. I get no weird burned taste.
On the first atty this happened to, I tried the 'dry burn' method, and it didn't work. The atty in fact went from producing like minimal vapor, to producing no vapor, so I figure it's dead somehow by the cleaning method. It however still warms up and gets cherry red, just no vapor. Again, the heating element still works, it just doesn't seem to wick juice down to the heating element to vape.
While waiting for my new atties this weekend, I've been limping along on the one I have, which lasted 1 week (!). A couple times I blew (from the threaded end) the atty out into a paper towel. I blew it out until no more juice was soaking into the paper towel, then put a fresh cart on it. This 'worked' a couple times, but lasted only about half a day.
After that, I thought maybe I was flooding the atty (I did hear the 'gurgling sound'). By trial and error over the weekend (If I would have known my backup atty was going to go out, I would have ordered with express shipping, but got standard ground instead

), I've found that if I blow from the threaded end, I can vape directly from from the atty for a few hits before repeating the process (blow, vape, blow). Last night, I pretty much did this for an hour until I couldn't produce any vapor this way. I turned the atty threads up, and let it sit for the night upside down; when I woke up this morning, I put a topped off cart on it, and it vaped fine for like 10 minutes.
Later today, I went for a vape and started having the same problem again; again if I did the no cart/blow/vape/blow routine, it worked. I think that something is gunked up in the wick, i.e. some part of the flavoring or VG or something. If I leave the cart on between vapes, the wick floods, but when I dry it out by vaping with no cart, I have to push the liquid through the wick by blowing it out to get the end of the wick near the heating element to work. Hopefully this pain in the rear method will work until my new atties get here; then I will try the boiling + 48 hour dry method to see if that cleans the wick or something.
Anyone aware of a place to look for photos of a 510 atty deconstructed? In trying to figure out my problem, I'm trying to get an idea of how the atty is actually put together.