Reply 20 of 26, by 640K!enough
The idea, if I'm understanding his intent, is to make sure you have only one source of 5V, and to connect it with only one very short (1 cm or less) piece of very thin wire, so that if something goes wrong, it will (hopefully) break the connection, somewhat like a fuse. The wire you're using appears to be stranded; that is, made up of many very thin wires in a bundle. He is suggesting that you take only one thin strand out of the insulation and use that to make the temporary connection for testing purposes.
I wouldn't try adding memory to the card until you confirm that it is usable. Find the source of the problem first, then test that it actually works to some extent. Consider adding memory only once you know that it can actually produce sound and is safe to keep in your system.