Purchase a reputable AC Adapter rated at exactly 24V and at least 0.83A as per the specifications written on the original adapter. For example, the Mean Well GE24I24-P1J. As this is a universal adapter, you will also need to purchase the appropriate Mean Well AC Plug for your region.

Using safety glasses and a wire cutter, cut the barrel connector off the end of the new AC Adapter.

Using a wire stripper, expose 1cm of copper on the ends of the positive and negative wires.