stuck 2nd stage faceplate

[miketsp]

The diaphragm is not compressed by the water pressure.

I am not saying that the diaphragm moved inwards, I am saying that the diaphragm became thinner under pressure.

Anything compressible will compress at depth. In the case I was referring to the diaphragm is a rubber disk with a smaller metal disk in the center which operates the 2nd stage valve lever.
The diaphragm was retained directly by the face plate which was threaded. (I have other regs where the diaphragm is not secured directly by the face-plate but by a separate retaining ring.
I can assure you that at depth, even going only finger tight, the face-plate turned an extra 90degrees. This had to come from the compression.

When loosened at depth and then retightened at the surface the face plate assumed the correct position.

 

[Diver0001]

I'm a DIYer with my SP stuff so I understand where you are coming from. Just the independence is satisfying. I finally had to dig up some pictures of the titan to understand the problem. .

The problem is that the retaining ring that the Titan was originally sold with doesn't have proper contours or any way to use a traditional tool. It's also put on so tight at the factory that God himself can't get it off..... Even with a well stocked workbench full of tools and an hour of trying I eventually decided to cut mine off with a hacksaw and replace it with a new one the first time I serviced it.

The new ones Aqualung has in circulation will take a tool to remove it.

R..