[SiriusHardware]

Hmm, surprisingly different from Colin's. That red stub will most likely be the 220V tap so, assuming your drive unit is a 220V-240V model - does it say so on a label on the unit? - you don't need to worry about it except for the fact that that tiny stub of metal sticking out from the end of the red insulation will have high AC voltage on it when the unit is powered. I would put some close fitting heatshrink over the end of that to make it impossible for anyone to come into contact with the core of the wire.

Wire colours black and white are 'American' for live and neutral respectively, it doesn't look as though the unit has a mains filter to complicate things, unlike Colin's.

All measurements and actions below to be carried out with the mains plug UNPLUGGED from the mains, I'm sure you know that, but we have to consider the possibility that someone we don't know could read this thread in the future and follow these instructions literally.

First of all verify that both fuses are OK, the one in the fuse holder in the unit and also the one in the mains plug - both should show continuity, obviously. While checking the fuse in the mains plug also check that the screws on all three pins are really tight, as it is very common for them to work loose over time.

As buggies said, you need to measure the resistance between live and neutral on the plug rather than looking for continuity, and of course the drive unit's mains switch needs to be in the ON position during that measurement. I seem to recall that the primary of Colin's transformer had quite a low DC resistance, in the order of tens of ohms.