So I go to the thrift shop around the corner, and I'm met with these two boxes in the electronics' section:
I'm sifting through these one by one, tangle by tangle, searching for a power adapter that conforms as close to what I expect. Alas, I find a MOTOROLA SPN5202B, which has the wrong fitting, and is just shy of some characters that match the SPN5504 model in the listing:
Nonetheless, the OUTPUT settings are identical. I continue searching one by one, tangle by tangle, and I come across something interesting:
Naturally, I plug it in to see if it fits:
It fits... Now, what I'm thinking is that I can just connect these two together--cutting some wires and taking the fitting from the latter to replace the fitting of the former. However, I'm also thinking how I don't feel like waiting for another Raspberry Pi from Amazon if I mess it up, so I'm wondering how exactly I can be sure that this is possible. I don't have a multimeter, but I can use my university's laboratory equipment.