You may have to check somewhere like digikey, but shipping a single jack is not cheap(shipping is more than the jack is worth). You would need the size(eg 7.9 X 5.5) for sure.
If it is too hard to find one, you may have able to swap the connector on the device(panel mount a new one with short wires to the board) and change to a matching connector on the power supply(I have done it for a project in the past.).