The spinning part can get pushed in and it then catches on the housing, you should be able to wiggle it free. I don’t remember if you need to disassemble most of it before you can reach that part, but I know I did. I used one of those iPhone repair kit plectrums to get between the housing and the spinner.
Again, recap the board first or have it recapped by someone else (some members here offer a recap service or use maccaps.com). That's the first thing you should do before fiddling with anything else on an SE/30 board. You could be right, fuses could be the culprit but a recap usually fixes most issues as illustrated by TjLaZer here. Bad caps and shorts are the #1 cause of malfunction.
Other than that, congrats on your A/B job. Gotta love the Noctua. Personally, I would have gone with one from their "pro" series because they're grey instead of cream/brown. But good choice nevertheless.