It checks out eh? I love a good mystery. Yup, Hittmans on the right path to solution. That fits into my second rule. You seem quite set on just replacing which is all good. I'm all for new stuff to fiddle with to make you happy. I'm just eyeing that scrap heap, heehee, I'd like at it. LOL.
I will ramble on in hopes of entertaining you and explain the origins of "the second rule". I used to be a broadcast engineer many moons ago. I used to thrive on fixing things, still do, but just not professionally anymore in that field. First rule is: Is it plugged in? Second rule is (and I'm not kidding you it still being April fools and all): Smack it!!! To quote one of my favorite Will Ferrell moves, "60% of the time, it works every time!" Now if it starts working, you could walk away without pulling out a single tool but since you brought all your tools anyhow, might as well figure out why that worked.
That still works for me today. I neglected to use that rule in my current job. I was set out all alone in the field and ran into a problem with a Boeing 737-800. During training there are constant reminders of how much everything costs on these planes. Hell a fuel cap alone on an Airbus (original manufactured) is $15,000. They get lost all the time, BTW, lol. So I am intimidated and gentle with this plane. I go to the operations manager and tell them the fuel panel doesn't work. He looks at me like I must be kidding. Then comes out and slams that panel door that scared the bajesus out of me. "There its working!", and looks at me like I just fell off the turnip truck. There ya' go, rule #2. In essence, check your connections. The rest of the rule actually get more surreal and are dependent on the situation, lol.
Regardless, replacement will surely work. So, now this discussion is mute.