Cleaning and Repair
I acquired several known good spare SMK keys from ebay, bringing my total investment to $115. Since I needed to disassemble the case to replace the key, I decided to do a thorough cleaning.
The mainboard was quite dusty and there was corrosion on the bottom of the case
The underside of the top and keyboard were not bad
A nice 99% isopropyl alcohol bath cleans things right up. Amazon has technical grade for $3/pint, cheaper than the lab grade and good enough for removing flux residue, it does the job here too.
I scrubbed everything with an old toothbrush and rinsed with more alcohol. While the rest of it dried I went to replace the broken key.
After cleaning the rest of the keys with alcohol and contact cleaner, I didn't need the other replacement keyswitches. A few keys are still stiff so I may have to go back in the future.
Reassembly is the reverse of disassembly
I left it to dry with a box fan blowing on it overnight. It powered right up. I'll tear into the powersupply another time.