GSU-25

I have a lot of catching up to do in terms of blogging. I hope to sit down and convert some of my work logs and photos to blog posts over the next couple of days. I will start with this post as a warning. The GSU-25 has a non-symmetric footprint! Yesterday I build a doubler for mounting both of my GSU-25s (primary and backup) in the common spot on the far left hand side of the mid-panel. I test fit the GSU-25s to the doubler and proceeded to rivet the doubler to the mid-panel.



I was intending to install the GSUs to the panel with the d-sub connections closes to the ground however when I went to bolt them in place (after I had everything riveted together the bolt holes did not line up. The holes were at least an 1/8" off. I spent a good 5 minutes trying to figure out how riveting the doubler in place deformed the layout that significantly. However, when I rotated the assembly 180 degrees everything was perfect on both GSUs. A quick glance at the mechanical drawing confirms it. The whole pattern is in fact not symmetric. In thinking about it, that was probably done on purpose such that if the LRU ever needed to be serviced or replaced that it could only be re-installed in the orientation that it was previously installed in.


Because Garmin accepts basically every install orientation (with a software configuration setting), I am going to keep this as is (upside down for me), and move on to the GTR-20 installation.