I was just getting all my year end stuff cleaned up and filing manuals and such. I ran across a Seelevel TSB that I had found when I went looking for information about protecting the sensors from damage and corrosion.
In the normal install instructions, they talk about the gauges having a conformal coating on them, but it is not the normal type you see in vehicle stuff which covers all the components and solder joints. Theirs is more of a slightly flexible solder mask, which leaves a lot of solder joints and components open to damage and corrosion.
It appears they know of the issues, and have for a while (2009 date on the TSB), so I am surprised it was not in the normal install information. It confirmed what I wanted to do, which was spray them with 3M undercoating.
Good information in the TSB in general.