Just go for new switch and bleed the system - quite straight forward and cheap - p.s. How's science teaching these days ? 15 years since I retired from teaching physics
probably like it was 15 years ago, stressful, full of pointless paper work but the kids make it worth it..... The holidays help as well
He's my hero - book binder's son who became a scientist and gave lecturers that everyone could understand - a sort of Victorian Brian Cox
Yes - Isaac was the most academically gifted - but he was apparently a miserable old git - Michael was more of a hands on scientist making all his own equipment