At first, I presumed my new Fun Park was just so happy to be restored, it decided to throw a small celebration in my honor. (Honestly, I think fireworks are a bit much, but these seemed commensurate to the achievement.)
Unfortunately, the party just won't stop... Sparkles and smoke abound!
The sister disc, on the other side of the relay, functions without incident. (She's a good neighbor.)
I've disassembled, cleaned all contacts properly, lubed, and adjusted for optimal contact on the wiper arm.
There are still regular sparks when the wiper advances, which continue intermittently on the disc, well after contact.
I'm left with the presumption that my next PBR order will include one of these:
If there's some other common thing I'm missing that could potentially cause this, I'm always happy to learn.
A video of the festivities here:
A sincere thank you to everyone that has contributed to the wealth of knowledge here.
It's truly given my new obsession some serious staying power.