Even if they look clean, a wet iso qtip (for me) every so often keeps that connection where it screws in good. A tiny bit of oil introduces much resistance. Also works for me with pen batteries. Upside down so iso doesn't get anywhere it shouldnt
I've never taken my atomizer apart, it's...
I tried my ta3 on a vong stem, and a simrell warhead stem. Imho, way too hot, way too much transfer. TA does what it says on the tin, it accumulates heat.
I'm using a glass wpa now, as it doesn't ever go out and about