HELL YEAH!!!!
I don't know exactly how cold it's supposed to feel but there's no (unwanted) humming and everything is kicking in; blowing cold air now!!!
The cap cost $45; more than I thought but I'm sure cheaper than having a service call. I'm going to keep my evening appt since they've got a $20 coupon for a "Safety Check." They can check my work and the refrig levels.
Can't thank everyone enough for chipping in. Jonathan, thanks a ton for the quick conversation and labels on the photo.
And thanks Chris for sending him a shirt on my behalf. I swear, whenever someone balks at making a token contribution to a site like this, remember these kinds of efforts and consider how much "value" there really is on here.