I had to replace both power bases in my 1984 310. Motors had failed in the old bases and the company who made them was out of business, no parts available.
Had mine replaced by an RV Interior shop. $200+ each as I recall - plus labor. The bases came with their own controls which were designed to be mounted on the seat, not the armrest as original.
If you want others to be happy, practice compassion.
If you want to be happy, practice compassion - The Dalai Lama
1984 310 Limited Motorhome
Courtesy Parking (W/S/E/Wi-Fi) on I-5 in Northern California, 70 miles from Oregon border