SD2 not extruding at all

eBay J-heads are notorious for being terrible.

I'd recommend getting a real J-head from hotends.com, or springing for an E3D (see signature). Most folks around here love it, but don't take my word for it since I sell them.

Wardjr sold me on the E3D just from descriptions in all his posts and I ordered from Filastruder.com (elmoret) and I immediately noticed an improvement. I randomly get clogs because I'm still a bit new to this, fiddle with settings, and swap PLA and ABS constantly. But the E3D is the absolute best. I personally recommend not messing with anything other than all metal hotends. I only wished I pulled my wallet out for the E3D the same day I ordered my SD2

FYI...I started getting 3 clogs per week with my PEEK and now average a clog every other month in an average of 30 solid printing hours per week. And I as well am not affiliated with any 3D printing outfit.

That is some form of torture you like down under

Enough said... You could have stopped at USPS.

And they wonder what is wrong with their business model   It's just too bad there isn't some other private company they could learn form... Oh wait  UPS and FedEx seem to be profitable I wonder how they do it

Hmmm. I could use some shotgun chokes maybe I should just order a filastruder.

OP We are seriously here to help.  A couple of options with your problem of clogging.  First off if your hot end truely is as clean as it says then it isn't clogged.  You are probably dealing with filament that is saturated with moisture.  You can try different methods to dry it out or better yet order up some Octave filament.  It isn't the best but it is fairly consistent and usually shows up dry and ready to print.  The other thing is if your z-height is set to close to the nozzle it can create back pressure that can make the extruder strip the filament.  The tension arm needs to be just right I like to set it to extrude 100 mm's and put tension on the filament.  This will allow you to adjust the tension to a point where it has the best pull.  Past that I would upgrade to an E3D.

It won't even push the filament through the nozzle on Manual, with me pushing it, so it isn't Z-height or stripped filament. What's puzzling is it has done this with four different heads, and mix-and-match parts from the four. I wouldn't have thought I got three bad hotends, especially since it started with the stock SD one. (They DO wear out, right? I've printed enough to wear a notch in the ABS filament guide.)

The filament I'm using is 3-week-old PLA from Push Plastic, stored in a tub with a big container of dessicant. It's dry enough to snap pieces off when bending.

+1 on E3D.

I went through 3 J-heads before I got sick of melting PEEK...Plus its nice to be able to regularly print at 250C+ with no worries

Those instructions should be fine.  The Sang board is much easier to flash firmware than the newer printer board.

Followed the advice and bought an E3D extruder from Filastruder. It does the exact same thing. It will print 2-3 layers, then the extruder sticks and the filament spirals out of the body. It isn't clogged- it will pull right back out. I've leveled the bed, I'm using the basic settings in Repetier, and I have the extrusion speed set lower. I've tried ABS and PLA, high temps, lower temps, different speeds, nothing works.

I got a Flashforge Dual Extruder for $500 on Ebay, and haven't had a single problem other than an occasional print not sticking to the bed. I took the thing camping, and it worked, outdoors, without even a bed leveling. I'm done with Solidoodle and Filastruder. This thing is going up on Ebay tonight, if anyone wants it. (Solidoodle 2 Expert with E3D extruder, spare standard extruder, 2 glass bed plates, and a bunch of printed parts.)