Vintage Singer 201K smouldering/sizzling motor!!?

I am new to vintage sewing machines and have recently got a Singer 201-2K, knee lever operated electric machine.

This afternoon I have been happily piecing a baby quilt on it. All was going well until I paused to do some seam pressing at my ironing board.

I noticed the machine was "buzzing" as though someone was very gently pressing on the knee lever (but not enough to get the needle to go up and down).

Then the needle did move!! I turned the machine on and off but it still buzzed. I tried again and it stopped for a moment before restarting.

Then all of a sudden there was an odd smell and a hiss/sizzle from the motor and a drop of liquid came out of the bottom!! At that point I disconnected the power!!

It was sold to me as having had new wiring but obviously I'm not so sure now!!

Can I fix this myself? My father-in-law is an electrician but has no experience of sewing machines and hubby is experienced in retiring motorbikes!!

Really disappointed :0( - I've tried three times with vintage machines, I have a Jones that worked for a bit then stopped (won't stitch), a Singer I got off eBay that wouldn't stitch and now this!!

Thanks for reading....

S x