So many issues I’ve made have been fron mechanical issues while probing. Board not properly screwed down in the housing amd grounds ount agains a chassis. A panavise with metal jaws shorts out the pcb. Test probes slip and short things out. confusing intermittent p
Heck, our facility was was taken down because someone had use a multimeter lead to probe the female side of a BMC connecrtor. now I always use a bnc adapter to bana probe lead and do things right
if you can put a bit more effort into yourbsetup to make even a quick troubkeshooting step a bit. The signal path is a master of this