My 99 once went out with a bang, blew a fuse and I jumped. It turned out to be capacitor and desparate need for rewiring (dates to 1934). I was told to throw the hole thing out, old electrics, out dated, and all that. After a bit of thought I decided to give it a chance and hand it in for repair, and it came back fine. Almost all machines older than the mid 1950s need rewiring, 1930s machine is usually shockingly risky. There's usually very little wrong with these old machine, and I have started to think of wiring as spendable parts like bobbin tyres and motor belts.