Newbie - '90 Holiday Rambler Limited DP - HWH Jack System

I purchased a 98 Holiday Rambler Endeavor that has similar type landing gear leveling system. I would put jacks down and then sometimes one of the jacks would lift up part way and not always
the same one. I checked fluid and it was fine. I ended up replacing control board and it has worked fine ever since. Control Board not that expensive. I hope emergency brake was on when you tried to drop leveling jacks. Brake has to be on before the system will work. The engine doesn't have to be running, just ignition turn on.