The Futaba "Attack" systems were AM systems. Most new equipment is FM, which won't work with an AM transmitter. You may also need to check the plugs on your servos. They may be the old "G" connectors, which had the flat pins projecting 90 degrees from how the wire entered the housing. Also, very likely, your receivers are old, wide-band receivers, which means that they can be "hit" by other transmitters on nearby channels. Old systems will also likely need new battery packs. All told, in order to bring your system up to modern specifications, meaning a new, narrow-band AM receiver with compatible servos and new battery packs, you'll likely have to spend as much or more than you'd spend to get a new, modern, narrow-band FM system or even a new 2.4 GHz FASST system.