Update: I opened my flash and it is a Diode with the bar on the left. My flash has an error code and will power up and charge the flash, but not operated.

It would be nice to know the resistor value you put in place of the missing one, but note the board looks like it calls it a D303 which is typically a name for a diode.

What is under the top plate? How many parts are replaceable. Switch button? Can you photograph one next time . Thanks

What are the springs for? Why are you replacing them? Is it part of the IS system and breaks I noticed my camera is making stabilization nose all the time even when not taking a picture.

Clean the hole with paper towel sb clean the hole with chemical cleaner and rag. The material must be prep for the shoe goo to stay and not peel off after a few uses. Sanding will help too as will applying glue past the hole onto a crease or tread pattern as Doug mentioned. Some goo inside the hole is OK as it helps hold in the patch just flatten it so there is no lump inside