[Julesomega]

Good to hear of another RF-D1 retrieved. If you want it to have a long life, do pay heed to the power dissipation of the regulator transistor. If you are going to use an unregulated power unit of nominally 12V you will need some additional heat sinking to stop it melting off the board. My added heatsink is not shown in my photos but I suppose it was about 2 × 5cm of 2mm thick ali, bent to fit around the transistor.
Alternatively, use a regulated supply set to about 7.5V which is about the lowest voltage that the set will operate on, or choose an unregulated supply that drops to that level when the set is switched on. There will be negligible power dissipated when it is off so you do not need to worry about leaving the supply on when the set is off.