I fixed it!. For future reference for anyone trying to replace the Cabinet Top Block (Shutter Module) here are some notes: I used the ifixit instructions for Sony Cyber-shot DSC-HX20V Outer Case Replacement. (1) I did the steps verbatim to the end of Step 11. (2) I did Steps 13-16, skipping the Step 12 calling for disconnection of the LCD ribbon cable (it was unnecessary.) (3) This is where I departed from the ifixit plans and did my own steps If you look inside the back of the camera at this point, near the top of camera just below the ON/OFF button, there is a silver screw inside the camera. Unscrew this. Gently pry open the front case away from the top module. It takes some finesse, but eventually if the front case is pried away, the top module can slide up and away from the top of the camera. Now you need to carefully release the one end of the ribbon cable. You can either do it on the main camera circuit board, or on the Cabinet Top Block module. To do this, you rotate up the back of the rear black...
For any one doing this kind of repair, you should know there exist heat shrink tubing that have a 3:1 shrink ratio (it shrinks to 1/3 the original diameter), which is extremely helpful in this kind of situation. Normal heat shrink tubing has a 2:1 shrink ratio (it shrinks to 1/2 the diameter).