I replaced mine with a little hydraulic ram I had lying around. It was about the size of a trailer brake ram, but double acting. It needed a restrictor in the line, and the spool valve turned down to almost minimum flow, but was a lot quicker and simpler than the electric one.
Having said that, I got a new Bogballe last year (great machines) and the electronic control is much better and faster than I remember rthe old one being.