So that generally means converting to a solid state regulator, but where to get one at short notice on a weekend? Then I had a thought.

Sure enough, pulled it apart and there's a neat little board containing the regulator portion only, separate to the socket mount and silly LED. It even fits in the original housing!


As expected the gauges are a little slower to rise but everything seems to work fine. According to the label this tiny thing is good for 3.1A so should be plenty for the instruments.