Am I hot or not?

[Sergeant Pluck]

OK, so I know this is schoolboy stuff that I should know, but I'm not proud!

I've got a BM accessory socket doubler which piggy-backs the existing socket down there by the gearbox, which I'm going to butcher for other purposes. It's made up of a brown lead and a red/yellow lead. Question is, which one is positive?!

 

[Tarka]

Brown should be negative earth.
Centre 'pin' should be positive. Outer casing should be negative earth.

 

[Sergeant Pluck]

Cheers Tarka.