Well, I got my components, recapped the NES, added a new input power jack, got a new power brick properly rated for it, cleaned it off thoroughly, powered it up and... dead. Totally $%&*!@ dead. No light even.
I'm wondering if maybe I bridged something in the power supply (lots of little resistors and such near the caps) or maybe I didn't bridge something that was previously. I did make sure to solder the RF housing plates where they connect to the PCB, and the A/V and RF connectors, and those few spots on the edges as well. The power jack fit properly (I bought 3 just to make sure one would fit) and it's not touching anything else. Not sure wtf the problem is.
I did buy a K tip for my TS100 which works amazing on those ground planes and for reflowing, and damn near anything else you need to heat up fast or that's a heat sink. Made quick work for reassembly.
Well, I guess at this point it's time to disassemble the whole thing again and start probing to see where the power is actually reaching (or not reaching). Maybe it's the voltage regulator. Maybe there's a damaged or corroded trace or faulty SMD component that isn't visibly damaged. Hopefully I can figure this out. Either way, it has been a fun learning experience to date.