RE: Old Futaba AM - What is salvageable?
Sorry, but if your transmitter is not narrow band, it is not legal to use. Non-narrow-band equipment became illegal to use in 1991. Conversion to narrow-band use, including replacement of the receiver, replacement of the battery packs, and upgrading the servos to new connectors would cost as much or more than a new, equivalent system.
If only the transmitter was upgraded, and the batteries replaced, and you risk flying with a wide-band receiver, then you'll likely pay 75%-80% of the cost of a brand-new system that's on FM and is narrow-band.
If the transmitter is already narrow-band, then it should cost you about $40.00-$50.00 to replace the battery packs.