A warning to all. A replacement SMAUG dragon is $518. I personally changed my dragon from one where the mouth didn't move unless assisted to one where the dragon didn't do anything except have the eyes light up. I would not attempt any of the below unless it is an effort to avoid the $518 replacement you are already mentally prepared to buy. I won't keep my Hobbit forever, so I figured I might as well fix it and enjoy it myself rather than discounting it by an equivalent amount down the road to have someone else enjoy it.
Before removing SMAUG, exhaust all software troubleshooting tests on pages B-20 to B-21 of the manual. Disassembly instructions and calibration steps are in section E1 of the manual here https://www.jerseyjackpinball.com/support/
Areas of interest are circled in pink.
Remove the dragon by removing the 3 screws (positions approximate) under the playfield. The dragon will drop if you don't have a hand on it when you remove the third screw.
Remove the 4 screws on the back of the dragon. The top of the jaw will drop when you do this if not braced.
Remove the 2 screws on the bottom part of the gold on the dragon.
You now have access to the part of the dragon that controls the open and close of the mouth. Section E1 of the manual tells how to calibrate here.
I tried the calibration instructions and failed.
After this I thought the problem may have been with the board which requires complete disassembly of the dragon. Don't disassemble any further than previously described if your only problem is mouth opening and closing. I disassembled further and managed to completely hose the left turn//right turn sensors in my dragon somehow.
Hopefully these pictures will help someone some day.
I have had a couple of PMs about buying my presumably non-working dragon. To the people that have asked about switching out their dragons for purely cosmetic reasons. Switching out the back, mouth, and gold pit of the dragon should be relatively simple. Changing out the top of the head should be possible, but would require switching the LEDs that light the eyes. I think it could be done, but I'd have to take it apart again to confirm.20190310_075154 (resized).jpgBack (resized).jpgGold (resized).jpgMouth (resized).jpgbottom (resized).jpg