Hacking the radio chip requires extending the wiring of the components. Firstly, de-solder the 6 connection points for the tuner. Solder some 120mm wire in place. I found that the extra wiring acts as an ariel, and interferes with the signal, wrapping these wires in tin foil seems to correct this problem. Then, de-solder the 3 volume connectors and solder in 3 new pieces of 120mm wire. Finally, de-solder the battery connectors, and add in a new AA battery case.