There were some systems that utilized a complicated receiving unit at the main power unit where the relay was actually in a box outside of the main unit. Hopefully you don't have that or you'll need to replace your power unit, hose, and RF system. But if you have a power unit and small receiver with low voltage wire going to a connect on the power unit then you can replace your RF and Hose. The RF Hose will fit your wall plates and the RF Receiver simply plugs into 110 vold near your unit and has a low voltage line to your unit. Here are the parts you need https://builtinvacuum.com/retail/shopretail.php?part_no=352G30RF,352GC30RF,145VR
. There are two hoses in the link, the difference is one has a pigtail cord and the other two pins that connect to electrical in the vacuum wall valve.