Cindy,
That large white wire isn't a wire, but a lead sheath covering some of the wires to protect them from the gears and oil.
The white stuff on it is lead oxide, a form of corrosion. Refrain from touching it, and if you do wash your hands as when ingested it can be toxic.
The smaller wires feel hard and brittle because they are cloth wrapped wire and as they age they do get hard. Don't touch them either.
There's really nothing that needs touched under there. Were that machine mine I'd use an aerosol electronic cleaner and hose the oil off of the wiring. Other than that it's best to just leave it alone if there's no broken insulation or bare wires.
As for the huge pics and dial up, I'm one of those that has trouble. With threads like this where there is just one pic, my computer will open it. But on threads where there are multiple pics, no way.
So, I really wouldn't worry about the wiring on that machine.
Joe